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The carcinogenicity of opium consumption was recently evaluated by a Working Group convened by the International Agency for Research on Cancer (IARC). We supplement the recent IARC evaluation by conducting an extended systematic review as well as a quantitative meta-analytic assessment of the role of opium consumption and risk for selected cancers, evaluating in detail various aspects of study quality on meta-analytic findings. We searched the published literature to identify all relevant studies on opium consumption and risk of selected cancers in humans through 31 October, 2022. Meta-relative risks (mRRs) and associated 95% confidence intervals (CIs) were estimated using random-effects models for studies of cancer of the urinary bladder, larynx, lung, oesophagus, pancreas, and stomach. Heterogeneity among studies was assessed using the I2 statistic. We assessed study quality and conducted sensitivity analyses to evaluate the impact of potential reverse causation, protopathic bias, selection bias, information bias, and confounding. In total, 2 prospective cohort studies and 33 case–control studies were included. The overall pooled mRR estimated for ‘ever or regular’ versus ‘never’ use of opium ranged from 1.50 (95% CI 1.13–1.99, I2 = 0%, 6 studies) for oesophageal cancer to 7.97 (95% CI 4.79–13.3, I2 = 62%, 7 studies) for laryngeal cancer. Analyses of cumulative opium exposure suggested greater risk of cancer associated with higher opium consumption. Findings were robust in sensitivity analyses excluding studies prone to potential methodological sources of biases and confounding. Findings support an adverse association between opium consumption and cancers of the urinary bladder, larynx, lung, oesophagus, pancreas and stomach.

Jesper Nors,1,2,* Trine Block Mattesen,1,* Deirdre Cronin-Fenton,3 Aurélie Mailhac,3 Jesper Bertram Bramsen,1,2 Kåre Andersson Gotschalck,2,4 Rune Erichsen,2,3,5 Claus Lindbjerg Andersen1,2 1Department of Molecular Medicine, Aarhus University Hospital, Aarhus, Denmark; 2Department of Clinical Medicine, Aarhus University Hospital, Aarhus, Denmark; 3Department of Clinical Epidemiology, Aarhus University Hospital, Aarhus, Denmark; 4Department of Surgery, Horsens Regional Hospital, Horsens, Denmark; 5Department of Surgery, Randers Regional Hospital, Horsens, Denmark*These authors contributed equally to this workCorrespondence: Claus Lindbjerg Andersen, Department of Molecular Medicine, Aarhus University Hospital, Palle Juul-Jensens Boulevard 99, Aarhus N, DK-8200, Denmark, Tel +45 78455319, Email cla@clin.au.dkPurpose: Colorectal cancer (CRC) recurrence is not routinely recorded in Danish health data registries. Here, we aimed to revalidate a registry-based algorithm to identify recurrences in a contemporary cohort and to investigate the accuracy of estimating the time to recurrence (TTR).Patients and Methods: We ascertained data on 1129 patients operated for UICC TNM stage I–III CRC during 2012– 2017 registered in the CRC biobank at the Department of Molecular Medicine, Aarhus University Hospital, Denmark. Individual-level data were linked with data from the Danish Colorectal Cancer Group database, Danish Cancer Registry, Danish National Registry of Patients, and Danish Pathology Registry. The algorithm identified recurrence based on diagnosis codes of local recurrence or metastases, the receipt of chemotherapy, or a pathological tissue assessment code of recurrence more than 180 days after CRC surgery. A subgroup was selected for validation of the algorithm using medical record reviews as a reference standard.Results: We found a 3-year cumulative recurrence rate of 20% (95% CI: 17– 22%). Manual medical record review identified 80 recurrences in the validation cohort of 522 patients. The algorithm detected recurrence with 94% sensitivity (75/80; 95% CI: 86– 98%) and 98% specificity (431/442; 95% CI: 96– 99%). The positive and negative predictive values of the algorithm were 87% (95% CI: 78– 93%) and 99% (95% CI: 97– 100%), respectively. The median difference in TTR (TTRMedical_chart-TTRalgorithm) was − 8 days (IQR: − 21 to +3 days). Restricting the algorithm to chemotherapy codes from oncology departments increased the positive predictive value from 87% to 94% without changing the negative predictive value (99%).Conclusion: The algorithm detected recurrence and TTR with high precision in this contemporary cohort. Restriction to chemotherapy codes from oncology departments using department classifications improves the algorithm. The algorithm is suitable for use in future observational studies.Keywords: time to recurrence, surveillance, chemotherapy, oncology

Purpose Taxane-based chemotherapy is the primary treatment for premenopausal breast cancer. Although being inconsistent, research suggests that variant alleles alter pharmacokinetics through reduced function of OATP transporters (limiting hepatic uptake), CYP-450 enzymes (hampering drug metabolism), and ABC transporters (decreasing clearance). Reduced function of DNA repair enzymes may hamper effectiveness through dose-limiting toxicities. We investigated whether single-nucleotide polymorphisms (SNPs) were associated with breast cancer recurrence or mortality in premenopausal women diagnosed with breast cancer. Methods We conducted a population-based cohort study of premenopausal women diagnosed with non-distant metastatic breast cancer in Denmark during 2007‒2011, when guidelines recommended adjuvant combination chemotherapy (taxanes, anthracyclines, and cyclophosphamide). Using archived formalin-fixed paraffin-embedded primary tumor tissue, we genotyped 26 SNPs using TaqMan assays. Danish health registries provided data on breast cancer recurrence (through September 25, 2017) and death (through December 31, 2019). We fit Cox regression models to calculate crude hazard ratios (HRs) and 95% confidence intervals (CIs) for recurrence and mortality across genotypes. Results Among 2,262 women, 249 experienced recurrence (cumulative incidence: 13%) and 259 died (cumulative incidence: 16%) during follow-up (median 7.0 and 10.1 years, respectively). Mortality was increased in variant carriers of GSTP1 rs1138272 (HR: 1.30, 95% CI 0.95–1.78) and CYP3A rs10273424 (HR: 1.33, 95% CI 0.98–1.81). SLCO1B1 rs2306283 (encoding OATP1B1) variant carriers had decreased recurrence (HR: 0.82, 95% CI 0.64–1.07) and mortality (HR: 0.77, 95% CI 0.60–0.98). Conclusion Docetaxel effectiveness was influenced by SNPs in GSTP1, CYP3A, and SLCO1B1 in premenopausal women with non-distant metastatic breast cancer, likely related to altered docetaxel pharmacokinetics. These SNPs may help determine individual benefit from taxane-based chemotherapy.

Background: To investigate how socioeconomic position (SEP) influences the effectiveness of cancer-directed treatment in premenopausal breast cancer patients in terms of breast cancer recurrence and mortality.Methods: Our cohort included all premenopausal women aged 18-55 years diagnosed with non-metastatic breast cancer and prescribed docetaxel-based chemotherapy in Denmark during 2007-2011. Population-based administrative registries provided data on SEP: marital status (married including registered partnership or single including divorced or widowed), cohabitation (cohabiting or living alone), education (low, intermediate or high), income (low, medium or high), and employment status (employed, unemployed or health-related absenteeism). For each SEP measure, we computed incidence rates, cumulative incidence proportions (CIPs) and used Poisson regression to compute incidence rate ratios and 95% confidence intervals (95% CIs) of recurrence and death. We stratified on ER status/tamoxifen to evaluate interaction.Results: Our cohort included 2,616 women; 286 (CIP: 13%) experienced recurrence and 223 (CIP: 11%) died during follow-up (median 6.6 and 7.2 years, respectively). Single women had both increased risks of recurrence (IRR: 1.45, 95% CI: 1.11-1.89) and mortality (IRR: 1.83, 95% CI: 1.32-2.52). Furthermore, we observed increased mortality in women with low education (IRR: 1.49, 95% CI: 0.95-2.33), low income (IRR: 1.37, 95% CI: 0.83-2.28), unemployment (IRR: 1.61, 95% CI: 0.83-3.13) or health-related work absenteeism (IRR: 1.80, 95% CI: 1.14-2.82), but smaller or no increased risk of recurrence. These findings were especially evident among women with ER+ tumors prescribed tamoxifen.Conclusions: Low SEP in premenopausal women with non-metastatic breast cancer was associated with increased mortality, but not always recurrence. This suggests underdetection of recurrences in certain groups. Poor prognosis in women with low SEP, especially single women, may partly be explained by tamoxifen adherence. Citation Format: Cathrine Hjorth, Per Damkier, Bent Ejlertsen, Timothy L Lash, Henrik T Sørensen, Deirdre Cronin-Fenton. Socioeconomic position and prognosis in premenopausal breast cancer: A population-based cohort study in Denmark [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P3-12-22.

Rationale: Overweight and obesity are associated with inferior prognosis in breast cancer. The explanation is considered multifactorial, and dyslipidemia may be a contributing factor. The purpose of this study was to examine the association between circulating lipids and breast cancer outcomes in patients enrolled in the Malmö Diet and Cancer Study (MDCS). Patients and methods: Circulating lipid levels were measured in the blood sampled upon enrollment in the female MDCS cohort (N=17,035). We identified all MDCS participants with incident invasive breast cancer diagnosed between 1991-2014. The follow-up time began at breast cancer diagnosis and continued until the first event of breast cancer recurrence, death, emigration, or five years of follow-up. We estimated the incidence rates of recurrence at five years and fit Cox regression models to compute crude and adjusted hazard ratios (HRs) with 95% confidence intervals (95% CI) of breast cancer recurrence as well as all-cause mortality according to cohort-specific tertiles of apolipoprotein A-1 (Apo A-1) and apolipoprotein B (Apo B). Results: We enrolled 850 eligible patients. During the five years of follow up, 90 invasive recurrences with over 3,807 person-years occurred. In multivariable analyses, high levels of Apo B were associated with an increased rate of recurrence (tertile 3 vs. 1, HR= 2.30 [95% CI: 1.13-4.68]). However, high levels of Apo B were not associated with all-cause mortality (tertile 3 vs. 1, HR= 1.23 [95%CI: 0.68-2.25]). We observed no associations between levels of Apo A-1 and recurrence (tertile 3 vs. 1, HR= 1.34 [95%CI: 0.70-2.58]) or all-cause mortality (tertile 3 vs. 1, HR=1.12 [95%CI: 0.61-2.05]). Conclusion: High pre-diagnostic levels of Apo B were associated with an increased risk of recurrence among breast cancer patients. Circulating Apo A-1 was not associated with breast cancer outcome. These results warrant further investigation into the importance of lipid-regulation in breast cancer patients. Citation Format: Sixten Harborg, Thomas P Ahern, Maria Feldt, Ann H Rosendahl, Deirdre Cronin-Fenton, Olle Melander, Signe Borgquist. Circulating lipids and breast cancer survival in the Malmö diet and cancer study [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P4-07-06.

Purpose: Late recurrence (i.e., ≥10 years after primary diagnosis) may have a more favorable prognosis than earlier recurrence. We investigated the risk of breast cancer (BC) death after late recurrence and identified prognostic factors. Furthermore, we compared survival between late and early recurrence. Methods: Using the Danish Breast Cancer Group and other nationwide databases, we identified women with early or late BC recurrence during 2004-2018, who were alive 6 months after recurrence. We followed them until BC death, death from other causes, emigration, ten years or 31/12/2018. We calculated mortality rates (MRs) per 1000 person-years (PY) and cumulative BC mortality, for early versus late recurrence and by characteristics of the primary tumor and of the late recurrence. Using Cox regression, we calculated adjusted hazard ratios (HRs) for BC death, accounting for death from other causes as competing risk. Results: Among 2,004 patients with late recurrence, 721 died of BC with a median survival time of 3 years (MR= 84.8 per 1000 PY; 10-year cumulative mortality=50%). Among 1,573 patients with early recurrence, 1,092 BC deaths occurred with a median survival time of 2.6 years (MR= 173.9 per 1000 PY; 10-year cumulative mortality=72%). Advanced stage at primary diagnosis, distant metastases, and adjuvant recurrence treatments were associated with increased mortality, while breast-conserving surgery at primary diagnosis, loco-regional recurrence, and recurrence surgery were associated with lower mortality. Conclusion: Patients with late recurrence had a more favorable prognosis than patients with early recurrence. The localization of recurrent disease was the main prognostic factor for BC death. Citation Format: Rikke Noergaard Pedersen, Lene Mellemkjær, Bent Ejlertsen, Mette Nørgaard, Deirdre Cronin-Fenton. Mortality after late breast cancer recurrence in Denmark [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P3-12-18.

Beta-blockers have shown anti-neoplastic effects in laboratory studies but epidemiologic evidence in relation to contralateral breast cancer (CBC) is sparse. We investigated post-diagnosis beta-blocker use and risk of CBC in a cohort of 52 723 women with breast cancer by using nationwide Danish health registers and the Danish Breast Cancer Group database. We defined post-diagnosis beta-blocker use as a time-varying covariate starting one year after a second prescription was redeemed. Cox proportional hazards regression was used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for CBC associated with beta-blocker use compared with non-use. We identified 1444 women with CBC of whom 209 women were beta-blocker users. We found an overall HR of 1.08 (95% CI: 0.93-1.27) for beta-blocker use and risk of CBC with no substantial variation according to cumulative amount, intensity or selectivity of beta-blocker use. Hence, our cohort study of women with breast cancer did not sustain a protective effect of beta-blocker use on risk of CBC, irrespective of beta-blocker type.

Purpose Breast cancer treatment is associated with adverse effects, which may delay return-to-work. Single nucleotide polymorphisms (SNPs) may influence the risk and severity of treatment toxicities, which in turn could delay return-to-work. We examined the association of 26 SNPs with return-to-work in premenopausal women with breast cancer. Methods Using Danish registries, we identified premenopausal women diagnosed with non-distant metastatic breast cancer during 2007‒2011, assigned adjuvant combination chemotherapy including cyclophosphamide and docetaxel. We genotyped 26 SNPs in 20 genes (ABCB1, ABCC2, ABCG2, CYP1A1, CYP1B1, CYP3A, CYP3A4, CYP3A5, GSTP1, SLCO1B1, SLCO1B3, ARHGEF10, EPHA4, EPHA5, EPHA6, EPHA8, ERCC1, ERCC2, FGD4 and TRPV1) using TaqMan assays. We computed the cumulative incidence of return-to-work (defined as 4 consecutive weeks of work) up to 10 years after surgery, treating death and retirement as competing events and fitted cause-specific Cox regression models to estimate crude hazard ratios (HRs) and 95% confidence intervals (CIs) of return-to-work. We also examined stable labor market attachment (defined as 12 consecutive weeks of work). Results We included 1,964 women. No associations were found for 25 SNPs. The cumulative incidence of return-to-work varied by CYP3A5 rs776746 genotype. From 6 months to 10 years after surgery, return-to-work increased from 25 to 94% in wildtypes (n = 1600), from 17 to 94% in heterozygotes (n = 249), and from 7 to 82% in homozygotes (n = 15). The HR showed delayed return-to-work in CYP3A5 rs776746 homozygotes throughout follow-up (0.48, 95% CI 0.26, 0.86), compared with wildtypes. Estimates were similar for stable labor market attachment. Conclusion Overall, the SNPs examined in the study did not influence return-to-work or stable labor market attachment after breast cancer in premenopausal women. Our findings did suggest that the outcomes were delayed in homozygote carriers of CYP3A5 rs776746, though the number of homozygotes was low.

Background Women treated for breast cancer (BC) often suffer genitourinary syndrome of menopause. These symptoms may be alleviated by vaginal estrogen therapy (VET) or menopausal hormone therapy (MHT). However, there are concerns of risks of recurrence of BC and death following treatment. Methods Our study included longitudinal data from a national cohort of postmenopausal women, diagnosed 1997-2004 with early-stage invasive estrogen receptor–positive nonmetastatic BC, who received no treatment or 5 years of adjuvant endocrine therapy. We ascertained prescription data on hormone therapy, VET or MHT, from a national prescription registry. We evaluated mortality and risk of recurrence associated with use of VET and MHT vs non-use using multivariable models adjusted for potential confounders. Results Among 8461 women who had not received VET or MHT before BC diagnosis, 1957 and 133 used VET and MHT, respectively, after diagnosis. Median follow-up was 9.8 years for recurrence and 15.2 years for mortality. The adjusted relative risk of recurrence was 1.08 (95% confidence interval [CI] = 0.89 to 1.32) for VET (1.39 [95% CI = 1.04 to 1.85 in the subgroup receiving adjuvant aromatase inhibitors]) and 1.05 (95% CI = 0.62 to 1.78) for MHT. The adjusted hazard ratios for overall mortality were 0.78 (95% CI = 0.71 to 0.87) and 0.94 (95% CI = 0.70 to 1.26) for VET and MHT, respectively. Conclusions In postmenopausal women treated for early-stage estrogen receptor–positive BC, neither VET nor MHT was associated with increased risk of recurrence or mortality. A subgroup analysis revealed an increased risk of recurrence, but not mortality, in patients receiving VET with adjuvant aromatase inhibitors.

Programmed cell death receptor ligand-1 (PD-L1) expression, KRAS (KRASm) and EGFR (EGFRm) mutations may influence non-small cell lung cancer (NSCLC) prognosis. We aimed to evaluate PD-L1 expression, KRASm, and EGFRm and survival among stage III unresected NSCLC patients. Using Danish registries, we collected data on stage III unresected NSCLC patients diagnosed 2001–2012 and paraffin-embedded tumor tissue from pathology archives. We assessed PD-L1 expression in tumors and tumor-infiltrating immune cells (ICs) by immunohistochemistry ($$\ge$$ ≥ 1% threshold for PD-L1+). We genotyped KRAS and EGFR. Follow-up extended from 120 days post-diagnosis to death, emigration, or 31/12/2014. We computed median survival using Kaplan–Meier methods, and hazard ratios (HRs) using Cox regression associating the biomarkers with death, adjusting for confounders. Among 305 patients, 48% had adenocarcinoma; 38% squamous cell carcinoma. Forty-nine percent had PD-L1+ tumors—51% stage IIIA and 26% KRASm. Few (2%) patients had EGFRm. Median survival in months was 14.7 (95% CI = 11.8–17.9) and 13.4 (95% CI = 9.5–16.3) in PD-L1+ and PD-L1− tumors, respectively. KRASm was not associated with death (HR = 1.06, 95% CI = 0.74–1.51 versus wildtype). PD-L1+ tumors yielded a HR = 0.83 (95% CI = 0.63–1.10); PD-L1+ ICs a HR = 0.51 (95% CI = 0.39–0.68). Tumor expression of PD-L1 did not influence survival. PD-L1+ ICs may confer survival benefit in stage III unresected NSCLC patients.

Julie Barberio,1 Thomas P Ahern,2 Richard F MacLehose,3 Lindsay J Collin,1 Deirdre P Cronin-Fenton,4 Per Damkier,5 Henrik Toft Sørensen,4 Timothy L Lash1 1Rollins School of Public Health, Emory University, Atlanta, GA, USA; 2The Robert Larner College of Medicine, University of Vermont, Burlington, VT, USA; 3University of Minnesota, Minneapolis, MN, USA; 4Aarhus University Hospital, Aarhus, Denmark; 5Odense University Hospital, Odense, DenmarkCorrespondence: Julie BarberioRollins School of Public Health, Emory University, Atlanta, GA, USAEmail julie.barberio@emory.eduPurpose: To compare the magnitude of bias due to unmeasured confounding estimated from various techniques in an applied example.Patients and Methods: We examined the association between dibutyl phthalate (DBP) and incident estrogen receptor (ER)-positive breast cancer in a Danish nationwide cohort (N=1,122,042). Cox regression analyses were adjusted for age and active drug compounds contributing to DBP exposure. We estimated the hazard ratios (HRs) that would have been observed had one of the DBP sources been unmeasured and calculated the strength of confounding by comparing to the fully adjusted HR. We performed a quantitative bias analysis (QBA) of the “unmeasured” confounder, using external information to specify the bias parameters. Upper bounds on the bias were estimated and E-values were calculated.Results: The adjusted HR for incident ER-positive breast cancer among women with high-level (≥ 10,000 cumulative milligrams) versus no DBP exposure was 2.12 (95% confidence interval 1.12 to 4.05). Removing each DBP source in isolation resulted in negligible change in the HR. The bias estimates from the QBA ranged from 1.00 to 1.01. The estimated maximum impact of unmeasured confounding ranged from 1.01 to 1.51. E-values ranged from 3.46 to 3.68.Conclusion: The impact of bias due to simulated unmeasured confounding was negligible, in part, because the unmeasured variable was not independent of controlled variables. When a suspected confounder cannot be measured in the study data, our exercise suggests that QBA is the most informative method for assessing the impact. E-values may best be reserved for situations where uncontrolled confounding emanates from an unknown confounder.Keywords: bias analysis, unmeasured confounding, the E-value

Purpose About 70% of women with breast cancer survive at least 10 years after diagnosis. We constructed an algorithm to ascertain late breast cancer recurrence-which we define as breast cancer that recurs 10 years or more after primary diagnosis (excluding contralateral breast cancers)-using Danish nationwide medical registries. We used clinical information recorded in medical records as a reference standard. Methods Using the Danish Breast Cancer Group clinical database, we ascertained data on 21,134 women who survived recurrence-free 10 years or more after incident stage I-III breast cancer diagnosed in 1987-2004. We used a combination of Danish registries to construct the algorithm-the Danish National Patient Registry for information on diagnostic, therapeutic and procedural codes; and cancer diagnoses from the Danish Pathology Registry, the Danish Cancer Registry and the Contralateral Breast Cancer database. To estimate the positive predictive value (PPV), we selected 105 patients who, according to our algorithm, had late recurrence diagnosed at Aarhus University Hospital. To estimate the sensitivity, specificity and negative predictive value (NPV), we selected 114 patients diagnosed with primary breast cancer at Aalborg University Hospital. We abstracted clinical information on late recurrence for patients with medical record-confirmed late recurrence at Aarhus University Hospital. Results Our algorithm had a PPV of late recurrence of 85.7% (95% CI: 77.5-91.3%), a sensitivity of 100.0% (95% CI, 39.8-100.0%), a specificity of 97.3 (95% CI, 92.2-99.4) and a NPV of 100% (95% CI, 96.6-100.0%). Conclusion Our algorithm for late recurrence showed a moderate to high PPV and high sensitivity, specificity and negative predictive value. The algorithm could be an important tool for future studies of late breast cancer recurrence.

Purpose To examine the association between statin use and risk of breast cancer recurrence in a national Danish cohort of postmenopausal breast cancer patients receiving aromatase inhibitors (AI) in the adjuvant setting. Patients and methods We enrolled all postmenopausal patients diagnosed with stage I–III estrogen receptor positive breast cancer during the years 2007–2017, assigned adjuvant AI treatment, and registered in both the Danish Breast Cancer Group database and the Danish Cancer Registry. We ascertained incident statin exposure (≥ 1 prescription post-diagnosis) from the Danish National Prescription Registry and modeled statins as a time-varying exposure lagged by 6 months. Follow-up began 7 months after diagnosis and continued to the first event of recurrence, death, emigration, 5 years elapsed, or 25th September 2018. We estimated incidence rates of recurrence at 5 years and used Cox regression models to compute crude and adjusted hazard ratios (HRs) with 95% confidence intervals (95% CI), comparing statin exposure with non-exposure. Results We enrolled 14,773 eligible patients. During the 5 years of follow-up, there were 32 recurrences in 3163 person-years of follow-up among statin-exposed patients, and 612 recurrences in 45,655 person-years among unexposed patients (incidence rate per 1000 person-years: 10.12 [95% CI 6.92–14.28] and 13.40 [95% CI 12.36–14.51], respectively). In multivariable models, any statin exposure was associated with a reduced rate of 5-year breast cancer recurrence (adjusted HR 0.72 [95% CI 0.50–1.04]). Considering only lipophilic statins as exposure the results were similar (adjusted HR 0.70 [95% CI 0.48–1.02]). Conclusions Statin use was associated with a reduced risk of breast cancer recurrence among postmenopausal patients diagnosed with early stage breast cancer who received adjuvant AI therapy.

Increased transparency in study design and analysis is one proposed solution to the perceived reproducibility crisis facing science. Systematic review and meta-analysis—through which individual studies on a specific association are ascertained, assessed for quality and quantitatively combined—is a critical process for building consensus in medical research. However, the conventional publication model creates static evidence summaries that force the quality assessment criteria and analytical choices of a small number of authors onto all stakeholders, some of whom will have different views on the quality assessment and key features of the analysis. This leads to discordant inferences from meta-analysis results and delayed arrival at consensus. We propose a shift to interactive meta-analysis, through which stakeholders can take control of the evidence synthesis using their own quality criteria and preferred analytic approach—including the option to incorporate prior information on the association in question—to reveal how their summary estimate differs from that reported by the original analysts. We demonstrate this concept using a web-based meta-analysis of the association between genetic variation in a key tamoxifen-metabolising enzyme and breast cancer recurrence in tamoxifen-treated women. We argue that interactive meta-analyses would speed consensus-building to the degree that they reveal invariance of inferences to different study selection and analysis criteria. On the other hand, when inferences are found to differ substantially as a function of these choices, the disparities highlight where future research resources should be invested to resolve lingering sources of disagreement.

Purpose Examine the association between circulating lipids and breast cancer outcomes in patients enrolled in the Malmö Diet and Cancer Study (MDCS). Patients and methods Circulating lipid levels were measured in blood sampled upon enrollment in the female MDCS cohort (N = 17,035). We identified all MDCS participants with incident invasive breast cancer diagnosed between 1991 and 2014. Follow-up time began at breast cancer diagnosis and continued until the first event of breast cancer recurrence, death, emigration, or 5 years of follow-up. We estimated the incidence rates of recurrence at 5 years and fit Cox regression models to compute crude and adjusted hazard ratios (HRs) with 95% confidence intervals (95% CI) of breast cancer recurrence as well as all-cause mortality according to cohort-specific tertiles of apolipoprotein A-1 (Apo A-1) and apolipoprotein B (Apo B). Results We enrolled 850 eligible patients. During the 5 years of follow-up, 90 invasive breast cancer recurrences were diagnosed over 3807 person-years. In multivariable analyses, high baseline levels of Apo B were associated with an increased rate of recurrence (tertile 3 vs. 1, HR = 2.30 [95% CI 1.13–4.68]). However, high baseline levels of Apo B were not associated with all-cause mortality (tertile 3 vs. 1, HR = 1.23 [95% CI 0.68–2.25]). We observed no associations between levels of Apo A-1 and recurrence (tertile 3 vs. 1, HR = 1.34 [95% CI 0.70–2.58]) or all-cause mortality (tertile 3 vs. 1, HR = 1.12 [95% CI 0.61–2.05]). Conclusion High pre-diagnostic levels of Apo B were associated with an increased risk of recurrence among breast cancer patients. Circulating Apo A-1 was not associated with breast cancer outcomes.

Signe Sørup,1 Bianka Darvalics,1 Jakob Schöllhammer Knudsen,1 Anne Staub Rasmussen,1 Cathrine Fonnesbech Hjorth,1 Søren Viborg Vestergaard,1 Azza Ahmed Khalil,2 Leo Russo,3 Dina Oksen,4 Emmanuelle Boutmy,4 Patrice Verpillat,4 Mikael Rørth,1,5 Deirdre Cronin-Fenton1 1Department of Clinical Epidemiology, Department of Clinical Medicine, Aarhus University & Aarhus University Hospital, Aarhus, Denmark; 2Department of Oncology, Aarhus University Hospital, Aarhus, Denmark; 3Worldwide Medical and Safety, Pfizer, Collegeville, PA, USA; 4Global Epidemiology, Merck Healthcare KGaA, Darmstadt, Germany; 5Department of Oncology, Rigshospitalet, Copenhagen, DenmarkCorrespondence: Signe Sørup, Department of Clinical Epidemiology, Aarhus University Hospital, Olof Palmes Allé 43-45, Aarhus, DK-8200, Denmark, Tel +45 871 68230, Fax +45 87 16 72 15, Email SigneSorup@clin.au.dkPurpose: To develop algorithms to identify number of lines of anti-neoplastic therapy per patient based on the Danish National Patient Registry (DNPR) and identify which algorithm has the highest percentage agreement with a reference standard of documentation in medical records.Patients and Methods: We included 179 patients diagnosed between January 1, 2012, and December 31, 2016, with stage II, III, or IV urothelial cell carcinoma or stage III or IV epithelial ovarian cancer, gastric adenocarcinoma, renal cell carcinoma, or non-small cell lung cancer (NSCLC). We developed two algorithms for number of lines of anti-neoplastic therapy based on dates and treatment codes (eg, “treatment with cisplatin” or “cytostatic treatment”) in the DNPR. First, to denote a change in line of therapy the “Time-based algorithm” used the number of days between consecutive administrations. Second, the “Drug-based algorithm” used information on drug names if available or the number of days between consecutive administrations if no drug names were specified. We calculated the percentage agreement between the algorithms setting the number of allowed days between consecutive administrations from 28 to 50 and the reference standard – information on anti-neoplastic therapy drugs abstracted from medical records and subsequently coded according to lines of anti-neoplastic therapy.Results: For the “Time-based algorithm”, the highest percentage agreement with the reference standard was found when using < 45 days between consecutive administrations (67.6%; 95% CI: 60.1– 73.8%). However, the percentage agreement was higher for the “Drug-based algorithm” using < 45 days between consecutive administrations for registrations where the drug name was unspecified (90.5%; 95% CI: 85.0– 93.7%).Conclusion: The algorithm for number of lines of anti-neoplastic therapy that had the highest percentage agreement with the reference standard (medical records) incorporated both registration of specific drug names and < 45 days between consecutive administrations if the drug name was unspecified in routinely recorded data from DNPR.Keywords: positive predictive value, medical records review, duration of chemotherapy, medical oncologic treatments, Denmark

Background: Statins and low-dose aspirin have been associated with a reduced breast cancer (BC) incidence, but results are inconsistent. Based on emerging evidence that parity, a protective factor for breast cancer, and these drugs modulate immunity, we hypothesized that the association between drug use and breast cancer risk may differ by parity. Objectives: To assess the associations of statin and low-dose aspirin use with BC incidence according to parity in French and Danish cohorts. Methods: We conducted two cohort studies, using data from the French E3N study and a Danish nationwide population-based cohort, respectively. From E3N, 51,482 women, mean age 65.5 years, were enrolled in 2005 and followed until 2014. Data on parity (here full-term pregnancies), drug use, and incident BC were acquired from questionnaires, a drug reimbursement database, pathology verified self-reports and the national cause-of-death registry, respectively. From nationwide health registries, we included all Danish women free of BC and aged 45 years in 2000-2005 (n=198,575), with follow-up to 2014. Use of the exposure drugs were defined as at least two reimbursements/filled prescriptions. In both cohorts, multivariable-adjusted Cox regression was used to compute hazard ratios (HR) for drug exposure, treated as time-varying lagged variables, and BC risk stratified by parity (0, 1, 2, 3+). Results: In E3N and Denmark, 1,878 and 5,436 incident BC cases occurred in a mean follow-up of 8.5 and 11.5 years, respectively. At the end of follow-up, 35% and 19% of E3N and 16% and 8% of the Danish cohort had been exposed to statins and low-dose aspirin, respectively. In E3N, effect modification was observed between parity and statins, but not low-dose aspirin. For statins, the HRs for use vs no use were 1.29 (0.97-1.72), 1.27 (0.99-1.65), 1.08 (0.91-1.27), and 0.76 (0.61-0.95) among women with 0, 1, 2, and 3+ full-term pregnancies, respectively (p-het=0.005). The corresponding estimates for low-dose aspirin were: 1.17 (0.80-1.71), 0.81 (0.54-1.20), 1.13 (0.90-1.43), and 1.22 (0.93-1.61; p-het=0.6). In contrast, the Danish data did not suggest any effect modification. HRs for use vs no use of statins were 0.82 (0.60-1.13), 1.05 (0.80-1.37), 0.91 (0.75-1.10), and 1.09 (0.83-1.44) among women with parity of 0, 1, 2, and 3+, respectively (p-het=0.3). For low-dose aspirin HRs were: 1.09 (0.75-1.59), 0.79 (0.54-1.15), 1.04 (0.82-1.32), and 0.99 (0.71-1.40; p-het=0.8). Conclusions: We observed effect modification by parity for the association between statins and breast cancer risk in the French but not the Danish cohort. Whether the age difference between the cohorts explains the inconsistent results should be explored. Citation Format: Julie A. Schmidt, Agnès Fournier, Manon Cairat, Aurélie Mailhac, Henrik Sørensen, Marc Gunter, Deirdre Cronin-Fenton. Parity, Use of Statins and Low-dose Aspirin, and Breast Cancer Risk – data from two large cohort studies [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P4-03-17.

Introduction Type 2 diabetes (T2D) is associated with obesity and other comorbidities involving multiple organ systems, which may increase the risk of postsurgical complications. Knowledge is sparse on the impact of T2D on the postsurgical outcome after breast cancer (BC) surgery in primary BC. Objectives To investigate the association of T2D and risk of complications after primary BC surgery, and according to neoadjuvant chemotherapy. Methods Our cohort included all Danish women diagnosed with early-stage operable BC during 1996-2018 registered in the Danish Breast Cancer Group clinical database. All patients had primary surgical treatment—mastectomy or breast conserving surgery. Information on prevalent T2D was collected from Danish medical and prescription registries, defining T2D via diagnostic codes or redemption of ≥2 prescriptions for glucose-lowering drugs. We defined postoperative complications as hospital admissions for medical or surgical complications (re-operations (excluding seromas), bleeding, infection, thrombosis, kidney or arterial cardiovascular disease) up to 30 days after primary BC surgery. We calculated the 30-day cumulative incidence function (CIF) of postoperative complications and used Cox regression to estimate hazard ratios (HR) and associated 95% confidence intervals (95% CI) overall, and stratified by the receipt of neoadjuvant chemotherapy, adjusting for potential confounders. Results Among 84,491 women with operable BC, 4,669 (5.5%) had prevalent T2D at time of BC surgery. Overall, 800 (17.1%) and 8,621 (10.8%) of BC patients with and without T2D developed postoperative complications corresponding to CIFs of 17% (95%CI: 16% - 18%) and 11% (95%CI: 10% - 11%), respectively, and a HR of 1.44 (95%CI: 1.34-1.56). 173 (3.7%) BC patients with T2D and 2,805 (3.5%) without T2D received neoadjuvant chemotherapy. Among those who did not receive neoadjuvant chemotherapy, the CIFs of postoperative complications was 17% (95% CI: 16% - 18%) and 11% (95% CI: 10% - 11%) for women with and without T2D, respectively, with a corresponding HR of 1.42 (95% CI: 1.31-1.53). For those with and without T2D who received neoadjuvant chemotherapy, the CIFs were 24% (95% CI: 18% - 30%) and 10% (95% CI: 9% - 11%), respectively, and with a corresponding HR of 2.08 (95% CI: 1.49-2.91). Conclusion Among women with BC, prevalent T2D at the time of primary BC surgery increases the risk of postoperative complications. This excess risk is particularly pronounced among patients who undergo neoadjuvant chemotherapy. Citation Format: Kasper Kjærgaard, Jannik Wheler, Looket Dihge, Peer Christiansen, Signe Borgquist, Deirdre Cronin-Fenton. The Impact of Type 2 Diabetes on Complications after Primary Breast Cancer Surgery: a Danish population-based cohort study [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P3-03-10.

Background: Adjuvant endocrine therapy (AET) approximately halves the risk of recurrence among the two-thirds of premenopausal breast cancer patients whose tumors overexpress the estrogen receptor (ER+). AET is recommended for a minimum five-year duration, but many premenopausal women discontinue AET prematurely. Adherence to AET is dynamic and influenced by many behavioral, societal, clinical, and genetic factors. Describing longitudinal patterns of AET adherence is an important first step towards identifying patients at highest risk of nonadherence–-and therefore recurrence–-who may benefit from adherence-enhancing interventions. We used group-based trajectory models to (1) describe AET adherence patterns, and (2) estimate associations between AET adherence and breast cancer recurrence in a Danish premenopausal, ER+ breast cancer cohort. Methods: Our cohort included 4,487 premenopausal women diagnosed with ER+, stage I–III primary breast cancer registered in the Danish Breast Cancer Group (DBCG) clinical database and treated with AET (2002–2011). We followed all patients from initiation of AET until recurrence, mortality, 10 years of follow-up, another primary malignancy, or the end of available follow-up. We excluded individuals with less than 1.5 years of follow-up as breast cancer recurrences that occur in this time are unlikely to be related to AET. At semi-annual follow-up visits, women were registered as having received (or not) a six-month supply of AET. We created daily indicators to determine if a woman had at least 80% of days covered by an AET fill within each six-month period for the first 4.5 years following AET initiation, yielding 9 variables indicating time-varying adherence. We used these indicators to characterize adherence trajectory groups. We defined recurrence as local, regional or distant metastases or contralateral breast cancer registered in the DBCG using follow-up data through 2017. We fit Cox regression models, adjusted for age and clinical factors, to estimate the association between adherence trajectory groups and recurrence. Results: We identified distinct trajectory groups in the cohort (Table 1)—high adherence (69%), slow decline (23%), and quick decline (8%). Women with quick decline were more likely to have stage I disease, have no positive lymph nodes, to not be treated with chemotherapy, and to have lumpectomy instead of mastectomy when compared to women with high adherence. Compared with high adherence women, the estimated rate of breast cancer recurrence was higher among those with slow decline (HR=1.12, 95%CI=1.04–1.21) and those with quick decline (HR=1.38, 95%CI=1.22–1.56). Conclusions: Group-trajectory modeling facilitated empirical description of AET adherence patterns in a premenopausal breast cancer cohort. As expected, women who more rapidly became AET-nonadherent were at increased risk of breast cancer recurrence compared with those who remained adherent. Future analyses will explore the contribution of specific socioeconomic, genetic, and clinical factors to AET adherence patterns, which will inform the design of interventions to improve AET adherence and reduce recurrence risk in breast cancer patients. Table 1. Trajectory group and the observed proportion of individuals adherent to their adjuvant endocrine therapy (AET) over 4.5 years of follow-up Citation Format: Kirsten M. Woolpert, Julie A. Schmidt, Thomas P. Ahern, Timothy L. Lash, Lindsay J. Collin, Bent Ejlertsen, Deirdre Cronin-Fenton. Group-based trajectories of endocrine therapy adherence and risk of recurrence in a Danish premenopausal breast cancer cohort [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P4-03-18.

Background Return-to-work (RTW) after breast cancer may be challenging for breast cancer survivors, especially those who experience adverse effects. Neuropathies are common adverse effect of taxane-based chemotherapy. Single nucleotide polymorphisms (SNPs) in genes related to taxane metabolism and transport, neural function, and neural- or DNA-repair may influence the risk of taxane-induced adverse effects, potentially impacting patient recovery and RTW. We examined the association of such SNPs with RTW in premenopausal breast cancer survivors. Methods We used Denmark’s nationwide population-based health registries to ascertain data on premenopausal women aged 18‒55 years diagnosed with non‒distant metastatic breast cancer during 2007‒2011, who were candidates for adjuvant combination chemotherapy including cyclophosphamide and docetaxel. Only women employed at diagnosis were included. We collected archived tumor tissue from nationwide pathology departments and genotyped 26 SNPs in 20 genes using TaqMan assays. For each SNP, we categorized the women as wildtype, homozygote or heterozygote. Follow-up continued from the date of primary surgery to the first of RTW (defined as 4 consecutive weeks of work), recurrence, maternity leave/childbirth, other malignancy, retirement, death, emigration or 25th September 2017. We computed the cumulative incidence of RTW and used Cox regression models to calculate unadjusted hazard ratios (HRs) and 95% confidence intervals (CIs) of RTW. Results We included 1,963 women. Women who were homozygotes for the phase 1 metabolizer CYP3A5 rs776746 (n=15) had lower cumulative incidence of RTW than wildtypes (n=1,600) and heterozygotes (n=249), 7%, 25% and 17% at six months, 57%, 87% and 88% at two years, and 82%, 94% and 94% at end of follow-up, respectively. Compared with wildtypes, CYP3A5 rs776746 homozygotes had delayed RTW throughout follow-up (HR 0-10 years: 0.48, 95% CI: 0.26, 0.86). No other SNPs were associated with RTW. Conclusions Among 26 SNPs, CYP3A5 rs776746 was associated with delayed RTW after breast cancer among premenopausal women. Our findings may help identify women at risk of a poor clinical course, who may benefit from enhanced supportive care during treatment and follow-up. Citation Format: Cathrine Hjorth, Per Damkier, Tore B. Stage, Søren Feddersen, Stephen Hamilton-Dutoit, Bent Ejlertsen, Timothy L. Lash, Henrik Bøggild, Henrik Sørensen, Deirdre Cronin-Fenton. The impact of single nucleotide polymorphisms on return-to-work after taxane-based chemotherapy in breast cancer [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P5-03-11.

Introduction Due to improvements in breast cancer (BC) diagnostics and treatment, the population of BC survivors is growing. BC treatments may have adverse effects that lead to an increased risk of developing type 2 diabetes mellitus (T2D). It is therefore important to investigate the risk of T2D in patients with BC in general and according to type of adjuvant BC treatment. Objectives To conduct a systematic review and meta-analysis investigating the association between early BC and the risk of subsequent T2D diagnosis. A secondary aim was to examine this association according to type of adjuvant BC treatment––chemotherapy and endocrine therapy (ET). Methods We searched PubMed and Embase using variations of the search terms breast cancer (population), ET, tamoxifen, aromatase inhibitors (AIs) and chemotherapy (exposures), and diabetes mellitus (outcome). Two authors screened papers for eligibility by title and abstract using Covidence and reviewed full texts of eligible papers. Guided by the Meta-analysis of Observational Studies in Epidemiology (MOOSE) checklist, study data were extracted. Using random-effects models, we calculated relative risks (RRs) and associated 95% confidence intervals (CIs) for the association between BC, adjuvant BC treatment (ET overall, tamoxifen, and AIs), and subsequent T2D. We used funnel plots to assess publication bias in the analyses. Results Among 16 eligible studies, 11 reported on T2D risk after BC, chemotherapy, or ET; five studies investigated more than one association. Compared with patients without BC, those with BC had elevated risk of T2D overall (RR=1.27, 95%CI=1.15-1.41), particularly those who received any ET (RR=1.23, 95% CI=1.16-1.32). Among BC patients only, risk of T2D was higher for those who received tamoxifen compared with those who did not receive tamoxifen (RR=1.19, 95% CI=1.13-1.25). Due to few studies, analyses investigating T2D risk after treatment with AIs and chemotherapy were inconclusive. Conclusion Our findings support an association between BC and subsequently elevated risk of T2D, particularly after tamoxifen use. Further research is needed to determine the impact of ET overall, AIs and chemotherapy on the incidence of T2D in patients with early BC. Funding This project was funded from the following source: The Novo Nordisk Foundation (NNF20OC0065928) Citation Format: Nanna Jordt, Kasper Kjærgaard, Signe Borgquist, Reimar W. Thomsen, Deirdre Cronin-Fenton. Breast Cancer and Subsequent Risk of Type 2 Diabetes Mellitus: A systematic review and Meta-Analysis [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P3-03-23.

Purpose: To examine the association between obesity and breast cancer outcomes and to describe socioeconomic position (SEP) in patients enrolled in the Malmö Diet and Cancer Study (MDCS) according to anthropometric measures. Patients and methods: The MDCS is a prospective cohort study that enrolled 17,035 female individuals in Malmö, Sweden from 1991 to 1996. The primary objective of the MDCS was to investigate associations between dietary patterns and cancer risk. Body mass index (BMI) and waist circumferences were measured upon enrollment, in the MDCS cohort. We identified all female MDCS participants with incident invasive breast cancer diagnosed between 1991 and 2014. The primary endpoint was breast cancer recurrence, defined as the time from breast cancer diagnosis until the earliest occurrence of invasive loco-regional recurrence or distant metastases. Follow-up time began at breast cancer diagnosis and continued until the first of breast cancer recurrence, death, emigration, or end of follow-up (June 8, 2020). BMI and waist circumference were categorized according to the World Health Organization guidelines as healthy weight (18.5-24.9 kg/m2 or waist < 81 cm), overweight (25.0-29.9 kg/m2 or waist 81-85 cm), and obese (≥ 30.0 kg/m2 or waist > 85 cm). Consistent with the Swedish socioeconomic classification, we categorized labor status into two groups—manual labor and non-manual labor. We categorized socioeconomic position (SEP) as low if patients had unskilled manual labor with < 2 years post-high school education, low-middle if skilled manual labor with > 2 years of post-high school education, high-middle if assistant non-manual labor with < 3 years of post-high school education, and high if non-manual labor with > 3 years of post-high school education. We fit Cox regression models to compute crude and adjusted hazard ratios (HRs) with 95% confidence intervals (95% CI) of breast cancer recurrence as well as all-cause mortality according to BMI and waist circumference. To evaluate effect measure modification, we stratified the Cox models by labor status, SEP, and smoking. Results: Among 1,099 breast cancer patients, 263 breast cancer recurrences were diagnosed over 12,810 person-years with a median follow-up of 11.1 years (interquartile range [IQR] was 6.6-16.2). The cohort consisted of 556 patients with healthy weight, 384 patients with overweight, and 159 patients with obesity. The median age at breast cancer diagnosis was 66.3 years (IQR: 61.2-72.8), and patients with obesity were older than patients with healthy weight (69.2 vs 64.9 years). In multivariable analyses, having obesity according to BMI was associated with increased rate of recurrence (HR= 1.44 [95% CI: 1.00-2.07]) and all-cause mortality (HR= 1.50 [95% CI: 1.13-1.98]) in comparison to having healthy weight. Similarly, having obesity according to waist circumference was associated with higher risk of recurrence (HR= 1.31 [95% CI: 0.98-1.77]) and all-cause mortality (HR= 1.72 [95% CI: 1.39-2.13]) in comparison to having healthy weight. When evaluating effect measure modification, we observed that obesity was associated with breast cancer recurrence in obese non-smoking women (HR= 1.66 [95% CI: 1.01-2.73]), in obese women with manual labor (HR= 2.45 [95% CI: 1.22-4.93]), and obese women with low SEP (HR= 2.55 [95% CI: 1.08-6.02]). We observed little evidence of an association between obesity and breast cancer recurrence among smokers (HR= 1.12 [95% CI: 0.43-2.92]), among patients with non-manual labor (HR= 0.94 [95% CI: 0.44-2.00]), or among patients with high SEP (HR= 1.47 [95% CI: 0.58-3.75]). Conclusion: Obesity defined by pre-diagnostic levels of BMI and waist circumference was associated with an increased risk of recurrence and all-cause mortality among breast cancer patients. The association between obesity and breast cancer recurrence seems dependent on patient characteristics such as labor status, socioeconomic position, and smoking. Citation Format: Sixten Harborg, Maria Feldt, Deirdre Cronin-Fenton, Susanne Dalton, Ann Rosendahl, Signe Borgquist. PD12-02 Obesity is associated with poor breast cancer prognosis, particularly among women with low socioeconomic position [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr PD12-02.

Background Low-dose aspirin irreversibly inhibits the cyclooxygenase enzymes COX-1 and COX-2, which catalyze the formation of prostaglandins and thromboxanes, inhibiting platelet aggregation. Platelets are thought to play a role in tumorigenesis. As such, aspirin may have a beneficial effect on breast cancer prognosis, but results to date are conflicting. Objectives To evaluate the association between aspirin use and breast cancer recurrence up to 23 years after primary diagnosis. Methods We included all women diagnosed with non-metastatic breast cancer during 1996-2004 registered in the Danish Breast Cancer Group (DBCG) clinical database. We obtained information on aspirin prescriptions (>= 2 prescriptions filled between cancer diagnosis and the landmark) from the Danish National Prescription Registry. Information on early and late (>10 years after primary diagnosis) recurrence was obtained using the DBCG database (for recurrence within the first 10 years after diagnosis) and for late recurrence via a previously described and validated algorithm, drawing on data from the Danish National Patient Registry, the Danish Pathology Registry, the Danish Cancer Registry and a contralateral breast cancer database. We used Cox regression to compute crude and adjusted hazard ratios (HRs) with 95% confidence intervals (CI) employing landmark analyses starting follow-up at years 5, 10, 15, and 20 after primary diagnosis. We adjusted for potential confounders including calendar year of diagnosis, menopausal status, comorbidities, estrogen receptor status, clinical stage, grade, surgery type, chemo- and endocrine therapy, diagnostic codes for alcoholism and obesity, as well as co-medications (angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, statins, bisphosphonates, metformin, digoxin, hormone replacement therapy, non-steroidal anti-inflammatory drugs, and vitamin K antagonists). We followed patients until recurrence, death, second cancer, loss to follow-up, or 31 December 2018. Results Among 21,684 women with non-metastatic breast cancer, 4,902 experienced recurrence during 242,427 person-years of follow-up. Our landmark analyses showed a reduced hazard of recurrence in the 5-, 10-, and 15-year landmark cohorts (5-year landmark adjusted HR = 0.80, 95% CI = 0.68, 0.94; 10-year landmark adjusted HR = 0.84, 95% CI = 0.71, 1.00, 15-year landmark adjusted HR = 0.83, 95% CI = 0.61, 1.14). The 20-year landmark analysis revealed an adjusted HR of 1.09 (95% CI = 0.49, 2.46). Conclusions The potential anti-cancer effect of aspirin appears most pronounced in the first 15 years after breast cancer diagnosis. Funding Elisabeth Solmunde is funded by the Danish Cancer Society (R320-A18464-B5768) and the Independent Research Fund Denmark (1149-00013B). This work was supported by grants to Deirdre Cronin-Fenton from the Danish Cancer Society (“Knæk Cancer” R147-A10100). Citation Format: Elisabeth Solmunde, Rikke N Pedersen, Mette Nørgaard, Lene Mellemkjær, Søren Friis, Bent Ejlertsen, Thomas P. Ahern, Deirdre Cronin-Fenton. Low-dose aspirin prescriptions and breast cancer recurrence: a Danish nationwide cohort study with up to 23 years of follow-up [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P4-03-02.

BACKGROUND: Breast cancer survivors may have increased risk of subsequent haematologic cancer. We compared their risk of haematologic cancers with the general population during 38 years of follow-up.METHODS: Using population-based Danish medical registries, we assembled a nationwide cohort of women diagnosed with incident non-metastatic breast cancer during 1980-2017, with follow-up through 2018. We compared breast cancer survivors with the general population by computing standardised incidence ratios (SIR) and 95% confidence intervals (CI).RESULTS: Among 101,117 breast cancer survivors, we observed 815 incident haematologic cancers (median follow-up: 7.9 years). We observed excess risk of acute myeloid leukaemia (AML) (SIR: 1.65, 95%CI: 1.33-2.01), particularly in women who received chemotherapy (SIR: 3.33, 95%CI: 2.24-4.75) and premenopausal women (SIR: 3.23, 95%CI: 2.41-4.25). The risk of acute lymphoid leukaemia (ALL) was increased (SIR: 2.25, 95%CI: 1.29-3.66), whereas the risk of chronic lymphoid leukaemia (CLL) was decreased (SIR: 0.66, 95%CI: 0.53-0.82). An additional analysis showed elevated risk of CLL 0-6 months after breast cancer diagnosis (SIR: 3.00 95%CI: 1.75-4.80).CONCLUSION: Compared to the general population, breast cancer survivors had elevated risk of AML, particularly when treated with chemotherapy. The risk of ALL was elevated, whereas the risk of CLL was lower. The higher risk of CLL in the first six months after diagnosis likely reflects surveillance bias-due to intensified diagnostic efforts at breast cancer diagnosis and treatment-prompting earlier detection. This has likely reduced the long-term risk of CLL in breast cancer survivors.

Background Hypoxia-inducible factor-1α (HIF-1α) is a transcription factor that facilitates the adaptation of cancer cells to hypoxic conditions and may be prognostic of breast cancer recurrence. We evaluated the association of HIF-1α expression with breast cancer recurrence, and its association with timing of breast cancer recurrence. Methods In this population-based case-control study, we included women diagnosed with stage I–III breast cancer between 1985 and 2001, aged 35–69 years, registered in the Danish Breast Cancer Group. We identified 541 cases of breast cancer recurrence among women with estrogen receptor (ER)-positive disease who were treated with tamoxifen for at least 1 year (ER+ TAM+). We also enrolled 300 breast cancer recurrence cases among women with ER-negative disease, not treated with tamoxifen, who survived at least 1 year (ER−/TAM−). Controls were recurrence-free breast cancer patients at the time of case diagnosis, matched to recurrence cases on ER/TAM status, date of surgery, menopausal status, cancer stage, and county of residence. Expression of HIF-1α was measured by immunohistochemistry on tissue microarrays. We fitted logistic regression models to compute odds ratios (ORs) and 95% confidence intervals (CIs) associating HIF-1α expression with recurrence, and with timing of recurrence. Results HIF-1α expression was observed in 23% of cases and 20% of controls in the ER+/TAM+ stratum, and in 47% of cases and 48% of controls in the ER−/TAM− stratum. We observed a near-null association between HIF-1α expression in both ER/TAM groups (ER+/TAM+ OR = 1.21, 95%CI 0.88, 1.67 and ER−/TAM− OR = 0.97, 95%CI 0.68, 1.39). HIF-1α expression was not associated with time to recurrence among women in the ER+/TAM+ stratum, but was associated with early recurrence among women in the ER−/TAM− stratum. Conclusion In this study, HIF-1α expression was not associated with breast cancer recurrence overall but may be associated with early recurrence among women diagnosed with ER− breast cancer.

Background To investigate how socioeconomic position (SEP) influences the effectiveness of cancer-directed treatment in premenopausal breast cancer patients in terms of breast cancer recurrence and mortality. Methods We conducted a cohort study nested in the ProBeCaRe (Predictors of Breast Cancer Recurrence) cohort (n = 5959). We identified all premenopausal women aged 18–55 years diagnosed with non-metastatic breast cancer and prescribed docetaxel-based chemotherapy in Denmark during 2007–2011. Population-based administrative registries provided data on SEP: marital status (married including registered partnership or single including divorced or widowed), cohabitation (cohabiting or living alone), education (low, intermediate, or high), income (low, medium, or high), and employment status (employed, unemployed, or health-related absenteeism). For each SEP measure, we computed incidence rates, cumulative incidence proportions (CIPs), and used Poisson regression to compute incidence rate ratios (IRRs) and 95% confidence intervals (CIs) of recurrence and death. We stratified on estrogen receptor (ER) status/tamoxifen to evaluate interaction. Results Our study cohort included 2616 women; 286 (CIP 13%) experienced recurrence and 223 (CIP 11%) died during follow-up (median 6.6 and 7.2 years, respectively). Single women had both increased 5-year risks of recurrence (IRR 1.45, 95% CI 1.11–1.89) and mortality (IRR 1.83, 95% CI 1.32–2.52). Furthermore, we observed increased 5-year mortality in women with low education (IRR 1.49, 95% CI 0.95–2.33), low income (IRR 1.37, 95% CI 0.83–2.28), unemployment (IRR 1.61, 95% CI 0.83–3.13), or health-related work absenteeism (IRR 1.80, 95% CI 1.14–2.82), but smaller or no increased risk of recurrence. These findings were especially evident among women with ER+ tumors prescribed tamoxifen. Overall analyses (follow-up max. 10 years) provided similar results. Conclusions Low SEP in premenopausal women with non-metastatic breast cancer was associated with increased mortality, but not always recurrence. This suggests underdetection of recurrences in certain groups. Poor prognosis in women with low SEP, especially single women, may partly be explained by tamoxifen adherence.

Background Extended, more effective breast cancer treatments have increased the prevalence of long-term survivors. We investigated the risk of late breast cancer recurrence (BCR), 10 years or more after primary diagnosis, and associations between patient and tumor characteristics at primary diagnosis and late BCR up to 32 years after primary breast cancer diagnosis. Methods Using the Danish Breast Cancer Group clinical database, we identified all women with an incident early breast cancer diagnosed during 1987-2004. We restricted to women who survived 10 years without a recurrence or second cancer (10-year disease-free survivors) and followed them from 10 years after breast cancer diagnosis date until late recurrence, death, emigration, second cancer, or December 31, 2018. We calculated incidence rates per 1000 person-years and cumulative incidences for late BCR, stratifying by patient and tumor characteristics. Using Cox regression, we calculated adjusted hazard ratios for late BCR accounting for competing risks. Results Among 36 924 women with breast cancer, 20 315 became 10-year disease-free survivors. Of these, 2595 developed late BCR (incidence rate = 15.53 per 1000 person-years, 95% confidence interval = 14.94 to 16.14; cumulative incidence = 16.6%, 95% confidence interval = 15.8% to 17.5%) from year 10 to 32 after primary diagnosis. Tumor size larger than 20 mm, lymph node–positive disease, and estrogen receptor–positive tumors were associated with increased cumulative incidences and hazards for late BCR. Conclusions Recurrences continued to occur up to 32 years after primary diagnosis. Women with high lymph node burden, large tumor size, and estrogen receptor–positive tumors had increased risk of late recurrence. Such patients may warrant extended surveillance, more aggressive treatment, or new therapy approaches.

Signe Sørup,1 Bianka Darvalics,1 Azza Ahmed Khalil,2 Marianne Nordsmark,2 Mette Hæe,2 Frede Donskov,3 Mads Agerbæk,2 Leo Russo,4 Dina Oksen,5 Emmanuelle Boutmy,5 Patrice Verpillat,5 Deirdre Cronin-Fenton1 1Department of Clinical Epidemiology, Department of Clinical Medicine, Aarhus University & Aarhus University Hospital, Aarhus, Denmark; 2Department of Oncology, Aarhus University Hospital, Aarhus, Denmark; 3Department of Clinical Medicine, Aarhus University, Aarhus, Denmark; 4Worldwide Medical and Safety, Pfizer, Collegeville, PA, USA; 5Global Epidemiology, Merck Healthcare KGaA, Darmstadt, GermanyCorrespondence: Signe SørupDepartment of Clinical Epidemiology, Aarhus University & Aarhus University Hospital, Olof Palmes Allé 43-45, DK-8200 Aarhus N, DenmarkTel +45 871 68398Email SigneSorup@clin.au.dkPurpose: Few studies have described real-world treatment patterns and survival before the widespread use of immune checkpoint inhibitors (ICIs). We aimed to describe anti-cancer treatment including the use of programmed cell death-1 and ligand-1 (PD-1/PD-L1) ICIs and overall survival (OS) in advanced cancer patients as a benchmarking real-world standard before widespread use of ICIs.Patients and Methods: Using nationwide Danish medical registries, we assembled cohorts of Danish patients with advanced non-small cell lung cancer (NSCLC) (n=12,283), urothelial carcinoma (n=2504), epithelial ovarian cancer (n=1466), gastric adenocarcinoma (n=1457), and renal cell carcinoma (RCC) (n=1261) diagnosed between 1/1/2013 and 31/12/2017. We describe anti-cancer treatment and OS using proportions, medians, and Kaplan–Meier methods.Results: Between 9% (ovarian cancer) and 25% (gastric adenocarcinoma) of patients did not receive anti-cancer treatment. The remaining patients received surgery, radiation therapy, and/or medical therapy. Chemotherapy was the most frequent medical therapy in all cohorts except for RCC (tyrosine kinase inhibitors). PD-L1/PD-1 ICIs were used in 7– 8% of the NSCLC and RCC cohorts—mainly as second or higher line treatments. OS was longest in patients starting treatment with surgery (eg 25.6 months [95%-confidence interval (CI)=21.9– 29.4] for NSCLC and 21.4 months [95%-CI=19.8– 23.5] for urothelial carcinoma) and shortest for radiation therapy (eg 3.9 months [95%-CI=3.6– 4.2] for NSCLC and 12.6 months [95%-CI=9.2– 17.5] for urothelial carcinoma). NSCLC patients starting with medical therapy had OS between these limits. Median OS for NSCLC patients starting treatment with PD-L1/PD-1 ICIs was 21.4 months (95%-CI=13.9-not estimable).Conclusion: Most patients with advanced NSCLC, urothelial carcinoma, epithelial ovarian cancer, gastric adenocarcinoma and RCC had poor OS in an era where only a minority received PD-L1/PD-1 ICIs. This information on treatment patterns and survival is important as a benchmarking real-world standard before widespread use of ICIs.Keywords: cancer, treatment, survival, immunotherapy, programmed cell death-1 immune checkpoint inhibitors, programmed cell death-ligand-1 immune checkpoint inhibitors

High‐dose corticosteroids have been associated with increased risk of serious infection in patients with metastatic melanoma treated with immune checkpoint inhibitors targeting cytotoxic T‐lymphocyte antigen 4. This potential association needs to be examined further among patients with other cancer types and for other immune checkpoint inhibitors. We examined whether receipt of high‐dose corticosteroids was associated with increased rates of hospitalization for infection among 981 Danish renal, urothelial, and lung cancer patients followed from first administration of programmed death receptor 1 (PD‐1)/programmed death ligand 1 (PD‐L1) immune checkpoint inhibitors. Our cohort analysis was based on the information from national medical registries. During follow‐up, 522 patients (53.2%) initiated treatment with high‐dose corticosteroids and 317 patients (32.3%) experienced at least one hospitalization for infection. In analyses adjusted for age, sex, and previous use of chemotherapy/targeted therapy, initiation of high‐dose systemic corticosteroids was associated with increased rate of hospitalization for infections (hazard ratio (HR) = 2.96, 95% confidence interval (CI) = 2.41–3.65) even in patients not receiving any chemotherapy/targeted therapy (HR = 3.66, 95% CI = 2.25–5.96). Our findings showed that high‐dose corticosteroid initiation is associated with hospitalization for infection in patients treated with PD‐1/PD‐L1 immune checkpoint inhibitors. Clinicians and patients should be aware of this risk of infection when initiating treatment with high‐dose corticosteroids., High‐dose corticosteroids have been associated with increased risk of serious infection in metastatic melanoma patients treated with immune checkpoint inhibitors (ICIs) targeting cytotoxic T‐lymphocyte antigen 4. The present study adds that use of high‐dose corticosteroids is also associated with increased rate of hospitalization for infection among lung, kidney, and urothelial cancer patients treated with ICIs targeting programmed death receptor 1 or programmed death ligand 1 even in patients who did not receive chemotherapy/targeted therapy.

BACKGROUND: PD-L1 expression on tumor cells (TCs) or immune cells (ICs) may be used as a prognostic marker for survival in patients with NSCLC. We characterized PD-L1 expression on TCs or ICs in a patient cohort with NSCLC to determine associations between PD-L1 expression and overall survival (OS), according to EGFR and KRAS mutation status.METHODS: Danish patients aged >18 years diagnosed with NSCLC before 2014 on first- (N = 491), second- (N = 368), or third-line (N = 498) therapy were included. Data were extracted from population-based medical registries. Tumor samples from pathology archives were tested for biomarkers. High PD-L1 expression was defined as expression on ≥25 % of TCs or ICs based on first diagnostic biopsy or surgical resection. KRAS and EGFR mutation status were tested using PCR-based assays. Cox regression analysis was used to compute adjusted HRs and associated 95 % CIs.RESULTS: PD-L1 TC and IC ≥ 25 % were observed in 24.3 %-31.0 % and 11.7-14.7 % of patients, respectively. EGFR and KRAS mutations were detected in 4.7 %-8.8 % and 26.5 %-30.7 % of patients, respectively. PD-L1 TC ≥ 25 % was not associated with survival advantage in first- (HR = 0.96, 95 % CI: 0.75-1.22), second- (1.08, 0.81-1.42), or third-line (0.94, 0.74-1.20) therapy. PD-L1 IC ≥ 25 % was associated with survival advantage in second-line (HR = 0.56, 95 % CI: 0.36-0.86) and third-line (0.69, 0.49-0.97) but not first-line (1.00, 0.70-1.41) therapy.CONCLUSION: No association was observed between PD-L1 TC ≥ 25 % and OS in any therapy line. PD-L1 IC ≥ 25 % may confer survival benefit among some patients who reach second-line therapy.

Statins (HMG-CoA reductase inhibitors) have antiinflammatory and possibly anticancer properties. We hypothesized that statin use is associated with lower risk of pancreatic cancer in patients with chronic pancreatitis. This nationwide population-based cohort study included all Danish patients diagnosed with incident chronic pancreatitis from 1 January 1996 to 31 December 2012. We used the Danish National Prescription Registry to ascertain information on statin prescriptions for members of the study population before and after their pancreatitis diagnosis. We computed crude incidence rates, incidence rate ratios (IRRs) and adjusted hazard ratios (HRs) with associated 95% confidence intervals (CIs) for pancreatic cancer, comparing statin users with nonusers. We computed HRs using Cox proportional hazards regression with statins treated as a time-varying exposure lagged by 1 year, adjusting for age, sex, socioeconomic status and individual comorbidities. The study included 8,311 chronic pancreatitis patients with a median age of 54 years. We observed 153 pancreatic cancers during 60,365 person-years of follow-up. The unadjusted IRR comparing statin users with nonusers was 1.00 (95% CI: 0.60–1.60). Adjustment for potential confounders only had a small impact on the estimate (adjusted HR: 0.90; 95% CI: 0.56–1.44). Our findings suggest that statin use is not associated with pancreatic cancer risk in patients with chronic pancreatitis.

Background and purpose — Selective serotonin reuptake inhibitors (SSRIs) are often used in the elderly and are associated with adverse effects. Therefore, it is important to ascertain the prevalence of SSRI use in fragile and surgery-treated hip fracture patients. Methods — This population-based prevalence study included Danish hip fracture patients aged ≥ 65 years operated in 2006–2016 (n = 68,607) and matched individuals from the background population (n = 343,020). Using Poisson regression, prevalence risk ratios (PRRs) with 95% confidence intervals (CIs) were estimated to compare hip fracture patients with the general population, and to estimate the association between hip fracture patient characteristics and SSRI prescriptions. Results — The prevalence of SSRI use among hip fracture patients was 23% compared with 12% in the general population. During 2006–2016, the prevalence decreased from 26% to 18% among hip fracture patients and from 13% to 10% in the general population. Factors associated with SSRI use in hip fracture patients were age 75–84 years (PRR 1.18, CI 1.13–1.23), age ≥ 85 years (PRR 1.17, CI 1.11–1.22), female sex (PRR 1.13, CI 1.09–1.17), unmarried status (PRR 1.15, CI 1.11–1.19), living in a residential institution (PRR 2.30, CI 2.19–2.40), Charlson comorbidity index (CCI) score 1–2 (PRR 1.50, CI 1.45–1.55), CCI score 3+ (PRR 1.62, CI 1.55–1.69), and several medications. Interpretation — The prevalence of SSRI use was high among hip fracture patients compared with the general population. Our data stress the importance of continued clinical awareness of frailty, comorbidity, and polypharmacy of hip fracture patients and the potentially adverse drug effects of SSRI treatment.

Simple Summary Obesity increases the risk of postmenopausal, hormone receptor-positive breast cancer and has been linked to a higher risk of recurrence and mortality. During obesity, adipose tissue can become dysfunctional, resulting in chronic low-grade inflammation. Crown-like structures in breast adipose tissue (CLS-B), composed of macrophages surrounding dead or dying adipocytes in a crown-like pattern, are a new histologic marker of local inflammation. In this review, we aim to evaluate the early evidence of CLS-B in breast cancer. There is consistent evidence that CLS-B are more frequently detected among obese compared to non-obese breast cancer patients. Additionally, several studies have found that CLS-B presence is associated with metabolic and inflammatory factors that contribute to breast cancer development and progression. However, more studies are needed to understand the potential clinical utility of CLS-B as a marker of breast cancer risk or prognosis. Abstract Obesity is an established risk factor for postmenopausal breast cancer and has been linked to worse breast cancer prognosis, most clearly for hormone receptor-positive breast cancers. The underlying mechanisms of the obesity–breast cancer association are not fully understood, but growing evidence points to the breast adipose tissue microenvironment playing an important role. Obesity-induced adipose tissue dysfunction can result in a chronic state of low-grade inflammation. Crown-like structures of the breast (CLS-B) were recently identified as a histologic marker of local inflammation. In this review, we evaluate the early evidence of CLS-B in breast cancer. Data from preclinical and clinical studies show that these inflammatory lesions within the breast are associated with local NF-κB activation, increased aromatase activity, and elevation of pro-inflammatory mediators (TNFα, IL-1β, IL-6, and COX-2-derived PGE2)—factors involved in multiple pathways of breast cancer development and progression. There is also substantial evidence from epidemiologic studies that CLS-B are associated with greater adiposity among breast cancer patients. However, there is insufficient evidence that CLS-B impact breast cancer risk or prognosis. Comparisons across studies of prognosis were complicated by differences in CLS-B evaluation and deficiencies in study design, which future studies should take into consideration. Breast adipose tissue inflammation provides a plausible explanation for the obesity–breast cancer association, but further study is needed to establish its role and whether markers such as CLS-B are clinically useful.

Background: Women treated for breast cancer (BC) often suffer genitourinary syndrome of menopause. These symptoms may be alleviated by vaginal or systemic hormonal treatment. However, there are concerns that hormonal treatment increases the risk of recurrence of breast cancer and death. Methods: Longitudinal data from a national cohort of postmenopausal women treated for early stage estrogen receptor positive non-metastatic BC from 1997 to 2004 was used in this observational study. Vaginal estrogen therapy (VET) or systemic hormonal replacement therapy (HRT) was assessed by cross-linking to the nationwide prescription database. Mortality and risk of recurrence associated with use of VET and HRT compared to non-use were assessed using multivariate models adjusted for potential confounders. Findings: Among 8461 women, who had not received VET or HRT before BC diagnosis, 1957 and 133 used VET and HRT, respectively, after diagnosis. The adjusted relative risk of recurrence with a median follow-up of 9·8 years was 1·08 (95% CI 0·89-1·32) for VET and 1·05 (95% CI 0·62-1·78) for HRT compared with never use. The adjusted hazard ratio (HR) for overall mortality, with a median follow-up of 15·2 years, were 0·78 (95% CI 0·71-0·87) and 0·94 (95% CI 0·70-1·26) for VET and HRT compared with never use. Analyses stratified by type of adjuvant endocrine therapy revealed an increased risk of recurrence of 1·39 (95% CI 1·04-1·85) associated with VET use during adjuvant treatment among women treated with aromatase inhibitors, without increased mortality (HR=0·94 (95% CI 0·70-1·26)). Interpretation: In postmenopausal women treated for early stage estrogen receptor positive BC, use of VET after diagnosis was associated with increased risk of recurrence but not mortality in patients receiving adjuvant aromatase inhibitors. The use of VET in patients treated with tamoxifen or no adjuvant endocrine therapy was not associated with increased risk of recurrence or mortality. Funding: Breast Friends Declaration of Interest: SC has received support from Breast Friends for the present manuscript. MJ has received institutional grants from Samsung BIOEPIS, Nanostring Technologies and Oncology Venture and has received support for attending scientific meeting from Novartis. PC has received honoraria and support for attending scientific meeting from Roche Denmark. BE has received institutional grants from AstraZeneca, Pfizer, Roche, Novartis, Samsung BIOEPIS, Nanostring Technologies and Oncology Venture and has received support for attending scientific meeting from MSD. FC and DCF declared no conflicts of interest. Ethical Approval: The Danish Data Protection Board approved the study and data were accessed through a secure server at Statistics Denmark (https://www.dst.dk), and only Danish research environments are granted authorization.

PURPOSE: The prevalence of breast cancer survivors has increased due to dissemination of population-based mammographic screening and improved treatments. Recent changes in anti-hormonal therapies for breast cancer may have modified the risks of subsequent urological and genital cancers. We examine the risk of subsequent primary urological and genital cancers in patients with incident breast cancer compared with risks in the general population.METHODS: Using population-based Danish medical registries, we identified a cohort of women with primary breast cancer (1990-2017). We followed them from one year after their breast cancer diagnosis until any subsequent urological or genital cancer diagnosis. We computed incidence rates and standardized incidence ratios (SIRs) with 95% confidence intervals (CIs) as the observed number of cancers relative to the expected number based on national incidence rates (by sex, age, and calendar year).RESULTS: Among 84,972 patients with breast cancer (median age 61 years), we observed 623 urological cancers and 1397 genital cancers during a median follow-up of 7.4 years. The incidence rate per 100,000 person-years was stable during follow-up (83 for urological cancers and 176 for genital cancers). The SIR was increased for ovarian cancer (1.37, 95% CI 1.23-1.52) and uterine cancer (1.37, 95% CI 1.25-1.50), but only during the pre-aromatase inhibitor era (before 2007). Moreover, the SIR of kidney cancer was increased (1.52, 95% CI 1.15-1.97), but only during 2007-2017. The SIR for urinary bladder cancer was marginally increased (1.15, 95% CI 1.04-1.28) with no temporal effects. No associations were observed for cervical cancer.CONCLUSION: Breast cancer survivors had higher risks of uterine and ovarian cancer than expected, but only before 2007, and of kidney cancer, but only after 2007. The risk of urinary bladder cancer was moderately increased without temporal effects, and we observed no association with cervical cancer.