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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.

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

We conducted a systematic review and meta-analysis investigating the association between overweight and outcome in triple-negative breast cancer (TNBC) patients. We searched PubMed and Embase using variations of the search terms triple-negative breast cancer (population), overweight and/or obesity (exposure), and prognosis (outcome). Based on the World Health Organization guidelines for defining overweight, we included longitudinal observational studies, which utilized survival statistics with hazard ratios (HRs) in our analysis. The included studies measured body mass index at the time of diagnosis of TNBC and reported disease-free survival and/or overall survival. Study quality was assessed with the Newcastle-Ottawa Scale and study data were extracted using the Meta-analysis of Observational Studies in Epidemiology (MOOSE) checklist, independently by two authors. Random-effects models were used to combine the effect sizes (HRs), and the results were evaluated and adjusted for possible publication bias. Thirteen studies of 8,944 TNBC patients were included. The meta-analysis showed that overweight was associated with both shorter disease-free survival (HR = 1.26; 95%CI: 1.09–1.46) and shorter overall survival (HR = 1.29; 95%CI: 1.11c1.51) compared to normal-weight. Additionally, our Bayesian meta-analyses suggest that overweight individuals are 7.4 and 9.9 times more likely to have shorter disease-free survival and overall survival, respectively. In conclusion, the available data suggest that overweight is associated with shorter disease-free and overall survival among TNBC patients. The results should be interpreted with caution due to possible publication bias.

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.

PurposePremenopausal women diagnosed with estrogen receptor (ER) positive breast cancer are prescribed 5–10 years of endocrine therapy to prevent or delay recurrence. Many women who initiate endocrine therapy fail to complete the recommended course of treatment. In this study, we evaluated the association between early discontinuation of adjuvant endocrine therapy and breast cancer recurrence in a cohort of premenopausal women.Patients and MethodsWe identified 4,503 premenopausal ER+ breast cancer patients who initiated adjuvant endocrine therapy and were registered in the Danish Breast Cancer Group clinical database (2002–2011). Women were excluded if they had a recurrence or were lost to follow-up less than 1.5 years after breast cancer surgery. Endocrine therapy was considered complete if the patient received at least 4.5 years of treatment or discontinued medication less than 6 months before recurrence. Exposure status was updated annually and modeled as a time-dependent variable. We accounted for baseline and time-varying confounders via time-varying weights, which we calculated from multivariable logistic regression models and included in regression models to estimate hazard ratios (HR) and accompanying 95% confidence intervals (CI) associating early discontinuation with breast cancer recurrence.ResultsOver the course of follow-up, 1,001 (22%) women discontinued endocrine therapy. We observed 202 (20%) recurrences among those who discontinued endocrine therapy, and 388 (11%) among those who completed the recommended treatment. The multivariable-adjusted estimated rate of recurrence was higher in women who discontinued endocrine therapy relative to those who completed their treatment (HR=1.67, 95% CI 1.25, 2.14).ConclusionThese results highlight the importance of clinical follow-up and behavioral interventions that support persistence of adjuvant endocrine therapy to prevent breast cancer recurrence.

Background Breast cancer survivors (BCS) may have increased risk of hypothyroidism, but risk according to treatment modality is unclear. We estimated the incidence of hypothyroidism in women with breast cancer, and according to cancer treatment. Methods Using nationwide registries, we identified all Danish women aged ≥ 35 years diagnosed with non-metastatic breast cancer (1996–2009). We matched up to five cancer-free women (controls) for each BCS. We excluded women with prevalent thyroid disease. Cancer treatment was chemotherapy with or without radiotherapy (RT) targeting the breast/chest wall only, or also the lymph nodes (RTn). We identified hypothyroidism using diagnostic codes, and/or levothyroxine prescriptions. We calculated the cumulative incidence, incidence rates (IR) per 1000 person-years, and used Cox regression to estimate hazard ratios (HR) and associated 95% confidence intervals (CIs) of hypothyroidism, adjusting for comorbidities. Results We included 44,574 BCS and 203,306 matched controls with 2,631,488 person-years of follow-up. BCS had a slightly higher incidence of hypothyroidism than controls [5-year cumulative incidence, 1.8% (95%CI = 1.7–1.9) and 1.6% (95%CI = 1.5–1.6), respectively]. The overall IR was 4.45 (95%CI = 4.25–4.67) and 3.81 (95%CI = 3.73–3.90), corresponding to an adjusted HR = 1.17 (95%CI = 1.11–1.24). BCS who received RTn with chemotherapy (HR = 1.74, 95%CI = 1.50–2.02) or without chemotherapy (HR = 1.31, 95%CI = 1.14–1.51) had an elevated risk of hypothyroidism compared with matched controls and compared with BCS who underwent surgery alone [HR = 1.71, 95%CI = 1.45–2.01 and HR = 1.36, 95%CI = 1.17–1.58, respectively]. Conclusions BCS have an excess risk of hypothyroidism compared with age-matched controls. BCS and those working in cancer survivorship settings ought to be aware that this risk is highest in women treated with radiation therapy to the lymph nodes and chemotherapy.

Background: Statins treat hyperlipidemia and prevent cardiovascular morbidity and mortality. Evidence suggests that they also have anti-neoplastic activity. Several studies show a reduced rate of breast cancer recurrence among lipophilic statin users (e.g., simvastatin), motivating calls for clinical trials of statins in breast cancer patients. We measured the impact of genetic variation in statin-metabolizing enzymes and drug transporters on the recurrence rate in simvastatin-treated breast cancer patients. Methods: We conducted a nested case-control study among Danish women diagnosed with non-metastatic, invasive breast cancer between 2004–2010 who had filled ≥1 prescription for simvastatin after diagnosis. Cases were all breast cancer recurrences from the source population; one control was matched to each case on cancer stage, estrogen receptor and hormone therapy status, calendar period of diagnosis, and duration of simvastatin exposure. We genotyped variants in simvastatin-metabolizing enzymes (CYP3A4/rs35599367 and CYP3A5/rs776746) and drug transporters (ABCB1/rs2032582 and SLCO1B1/rs4149056), and estimated their association with recurrence with logistic regression models. Results: We observed protective (though imprecisely-measured) associations between variants in genes encoding drug transporters (ABCB1 and SLCO1B1) and simvastatin-metabolizing enzymes (CYP3A4 and CYP3A5) and breast cancer recurrence in simvastatin-treated women. For example, carrying two variant alleles in ABCB1 was associated with a 31% lower rate of recurrence (multivariable OR = 0.69, 95% CI: 0.31, 1.5). Conclusion: Our study provides weak evidence to support the use of genetic variation in ABCB1, SLCO1B1, CYP3A4, and CYP3A5 as biomarkers of breast tumor response to simvastatin. Validation of these findings within adjuvant clinical trials is encouraged.

ObjectiveWe examined the risk of primary gastrointestinal cancers in women with breast cancer and compared this risk with that of the general population.DesignUsing population-based Danish registries, we conducted a cohort study of women with incident non-metastatic breast cancer (1990–2017). We computed cumulative cancer incidences and standardised incidence ratios (SIRs).ResultsAmong 84 972 patients with breast cancer, we observed 2340 gastrointestinal cancers. After 20 years of follow-up, the cumulative incidence of gastrointestinal cancers was 4%, driven mainly by colon cancers. Only risk of stomach cancer was continually increased beyond 1 year following breast cancer. The SIR for colon cancer was neutral during 2–5 years of follow-up and approximately 1.2-fold increased thereafter. For cancer of the oesophagus, the SIR was increased only during 6–10 years. There was a weak association with pancreas cancer beyond 10 years. Between 1990–2006 and 2007–2017, the 1–10 years SIR estimate decreased and reached unity for upper gastrointestinal cancers (oesophagus, stomach, and small intestine). For lower gastrointestinal cancers (colon, rectum, and anal canal), the SIR estimate was increased only after 2007. No temporal effects were observed for the remaining gastrointestinal cancers. Treatment effects were negligible.ConclusionBreast cancer survivors were at increased risk of oesophagus and stomach cancer, but only before 2007. The risk of colon cancer was increased, but only after 2007.

BACKGROUND: Obesity is associated with metabolic abnormalities that predispose patients to increased cancer risk. Contemporary data on the long-term risk of specific cancers are sparse among patients with hospital-diagnosed overweight and obesity.OBJECTIVES: To examine the overall cancer incidence and specific site-related cancer incidences among patients with overweight and obesity, compared to the general Danish population.METHODS: For this 40-year (1977-2016), nationwide, Danish cohort study, we reviewed medical databases to identify individuals with hospital-based overweight and obesity diagnoses. We computed age- and gender-standardized incidence ratios (SIRs) for subsequent cancer compared to the general population.RESULTS: We observed 20 706 cancers among 313 321 patients diagnosed with overweight and obesity (median age 43 years; median follow-up 6.7 years, range 1-40 years) compared to the 18 480 cancers expected; thus, the SIR was 1.12 [95% confidence interval (95% CI): 1.11-1.14]. The SIR associated with overweight and obesity was increased with concomitant comorbidities, like type 2 diabetes (SIR: 1.18; 95% CI: 1.13-1.23) and alcoholism-related diseases (SIR: 1.62; 95% CI: 1.45-1.82). The SIR was 1.31 (95% CI: 1.28-1.34) for cancers previously identified as obesity-related, including pancreatic (SIR: 1.38; 95% CI; 1.27-1.49) and postmenopausal breast cancer (SIR: 1.14; 95% CI: 1.09-1.19). Obesity/overweight status also elevated the SIRs for haematological (SIR: 1.24; 95% CI: 1.18-1.29) and neurological cancers (SIR: 1.19; 95% CI: 1.11-1.27]. In contrast, SIRs were 1.01 (95% CI: 0.97-1.05) for immune-related cancers, 0.88 (95% CI: 0.82-0.95) for malignant melanoma, and 0.88 (95% CI: 0.85-0.92) for hormone-related cancers, other than postmenopausal breast cancer.CONCLUSION: In this large cohort study, overweight and obesity was associated with increased risk of several common cancers.

Background: Tamoxifen and its metabolites compete with estrogen to occupy the estrogen receptor. The conventional dose of adjuvant tamoxifen overwhelms estrogen in this competition, reducing breast cancer recurrence risk by nearly half. Phase I metabolism generates active tamoxifen metabolites, and phase II metabolism deactivates them. No earlier pharmacogenetic study has comprehensively evaluated the metabolism and transport pathways, and no earlier study has included a large population of premenopausal women. Methods: We completed a cohort study of 5,959 Danish nonmetastatic premenopausal breast cancer patients, in whom 938 recurrences occurred, and a case–control study of 541 recurrent cases in a cohort of Danish predominantly postmenopausal breast cancer patients, all followed for 10 years. We collected formalin-fixed paraffin-embedded tumor blocks and genotyped 32 variants in 15 genes involved in tamoxifen metabolism or transport. We estimated conventional associations for each variant and used prior information about the tamoxifen metabolic path to evaluate the importance of metabolic and transporter pathways. Results: No individual variant was notably associated with risk of recurrence in either study population. Both studies showed weak evidence of the importance of phase I metabolism in the clinical response to adjuvant tamoxifen therapy. Conclusions: Consistent with prior knowledge, our results support the role of phase I metabolic capacity in clinical response to tamoxifen. Nonetheless, no individual variant substantially explained the modest phase I effect on tamoxifen response. Impact: These results are consistent with guidelines recommending against genotype-guided prescribing of tamoxifen, and for the first time provide evidence supporting these guidelines in premenopausal women.

BACKGROUND: Approximately 20–40% of patients diagnosed with breast cancer will experience a recurrence up to 20 years after their original diagnosis. 17?-hydroxysteroid dehydrogenase 1 and 2 (HSD17B1 and HSD17B2, respectively) regulate intratumoral concentrations of oestradiol, which promotes growth and proliferation of hormone dependent tumours. Breast carcinomas with increased HSD17B1, without a corresponding increase in HSD17B2, expression may become resistant to tamoxifen therapy by producing locally higher concentrations of oestradiol, which compete with tamoxifen and its metabolites for binding to the oestrogen receptor (ER). MATERIALS AND 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 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, stage, and county or residence. Expression of HSD17B1 and HSD17B2 were measured by immunohistochemistry on tissue microarrays. We fit logistic regression models to compute odds ratios (ORs) and 95% confidence intervals (CIs) associating the HSD17B1:HSD17B2 ratio (>1 vs. ?1)—and each enzyme’s independent expression—with recurrence. RESULTS: We found no association between the HSD17B1:HSD17B2 ratio and breast cancer recurrence in either ER/TAM stratum (ER+/TAM+: OR=1.03, 95% CI: 0.78, 1.40; ER?/TAM?: OR=1.02, 95% CI: 0.77, 1.19). Associations for expression of each individual enzyme were also near null. CONCLUSION: The ratio of HSD17B1 expression to HSD17B2 expression was not associated with breast cancer recurrence in this study.

AIMS: To examine the validity of the diagnoses of acute and chronic pancreatitis registered in the Danish National Patient Registry.METHODS: We identified all patients in the Danish National Patient Registry admitted to two Danish hospitals with acute or chronic pancreatitis from 1996 to 2013. From this population, we randomly sampled 100 patients with acute pancreatitis and 100 patients with chronic pancreatitis. For each cohort, we computed the positive predictive values and associated 95% confidence intervals (CIs) for the discharge diagnosis of acute or chronic pancreatitis using medical records as the gold standard.RESULTS: We identified 2617 patients with acute pancreatitis and 1284 patients with chronic pancreatitis discharged from either of the two hospitals during the study period. Of these, 776 (19.9%) had a diagnosis of both acute and chronic pancreatitis and are thus present in both cohorts. From the 200 sampled patients, a total of 138 (69.0%) medical records were available for review. The positive predictive value for a diagnosis of acute pancreatitis in the Danish National Patient Registry was 97.3% (95% CI 90.5-99.2%) and for chronic pancreatitis 83.1% (95% CI 72.2-90.3%).CONCLUSIONS: The validity of diagnoses of acute and chronic pancreatitis registered in the Danish National Patient Registry since 1996 is generally high.

BACKGROUND: We aimed to examine the association between acute pancreatitis, a potential early symptom of pancreatic cancer, and pancreatic cancer stage, treatment, and prognosis.METHODS: We conducted a cohort study of patients diagnosed with pancreatic cancer during 2004-2017 using population-based registry data from Denmark and Surveillance, Epidemiology, and End Results (SEER) data linked with Medicare claims from the United States (US), which include individuals aged 65 + . We ascertained information on acute pancreatitis diagnoses up to 90 days before pancreatic cancer and followed them for a maximum of five years. We assessed overall survival difference at 30 days, six months, and one, three and five years, comparing patients with and without coexistence of acute pancreatitis. Secondary outcomes were cancer stage and treatment.RESULTS: We identified 12,522 Danish and 37,552 US patients with pancreatic cancer (median age 71 and 78 years, respectively). In the Danish cohort, 1.4 % had acute pancreatitis before pancreatic cancer vs. 5.9 % in the US cohort. After five years of follow-up, the survival difference was 6.1 % (95 % CI: [-0.4 %, 12.6 %]) in Danish and 1.7 % (95 % CI: [0.8 %, 2.7 %]) in US patients, comparing patients with and without acute pancreatitis. Patients with acute pancreatitis had lower prevalence of metastatic tumors at diagnosis (Denmark: 42.5 % vs. 48.7 %; US: 34.4 % vs. 45.9 %) and higher resection frequencies (Denmark: 20.1 % vs. 12.1 %; US: 16.1 % vs.11.3 %) than patients without acute pancreatitis.CONCLUSIONS: Pancreatic cancer patients with acute pancreatitis diagnosed up to 90 days before cancer diagnosis had earlier stage at diagnosis and better survival than patients without acute pancreatitis.

Background Preclinical studies have shown both pro- and antineoplastic effects of antihistamines. Here, we evaluated the effect of H1 antihistamines on contralateral breast cancer (CBC) risk, and whether cationic amphiphilic (CAD) antihistamines could increase the sensitivity to chemotherapy. Methods From the Danish Breast Cancer Group clinical database, we identified all women aged ≥20 years with a first-time diagnosis of breast cancer during 1996–2012. Information on drug use, CBC and potential confounding factors was retrieved from nationwide registries. Using Cox proportional hazard regression models, we calculated hazard ratios (HRs) and 95% confidence intervals (CIs) for CBC associated with H1-antihistamine use. Results We identified 52,723 patients with breast cancer with a total of 310,583 person-years of follow-up. Among them, 1444 patients developed a new primary tumour in the contralateral breast. Post-diagnosis use of H1 antihistamines (≥2 prescriptions) was not strongly associated with CBC risk (HR 1.08, 95% CI: 0.90–1.31) compared with non-use ( Conclusions Taken together, our findings do not suggest any association of H1-antihistamine use with CBC development.

Laboratory studies suggest that inhibition of the cyclooxygenase (COX)-2 enzymes inhibits breast cancer development. We aimed to evaluate whether postdiagnosis use of COX-2 selective or other nonaspirin nonsteroidal anti-inflammatory drugs (NSAIDs) reduce the risk of contralateral breast cancer (CBC) among Danish breast cancer patients. From the clinical database of the Danish Breast Cancer Group, we identified 52,723 women diagnosed with breast cancer between 1996 and 2012. Data on nonaspirin NSAID use, CBC and potential confounding variables were obtained from nationwide registries. We defined postdiagnosis use (two or more prescriptions) as a time-varying covariate with a one-year lag. Cox proportional hazard regression models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for CBC associated with nonaspirin NSAID use. During a median follow-up of 4.8 years (interquartile range: 2.3-9 years), 1,444 patients were diagnosed with CBC. Overall, postdiagnosis use of nonaspirin NSAID was associated with an adjusted HR for CBC of 0.98 (95% CI: 0.87-1.11). The HRs did not vary substantially with duration or intensity of nonaspirin NSAID use. Moreover, similar associations were found for COX-2 selective (HR: 1.02; 95% CI: 0.85-1.23) and nonselective (HR: 0.96; 95% CI: 0.82-1.13) nonaspirin NSAIDs. In conclusion, our nationwide cohort study of breast cancer patients does not suggest a reduced risk of CBC with nonaspirin NSAID use regardless of the COX-2 selectivity.

Objective The association between thyroid dysfunction and gastrointestinal cancer is unclear. Design We conducted a nationwide population-based cohort study to examine this potential association. Methods We used Danish medical registries to assemble a nationwide population-based cohort of patients diagnosed with hyperthyroid or hypothyroid disease from 1978 to 2013. We computed standardized incidence ratios (SIRs) with corresponding 95% CIs as measures of the relative risk of each cancer, comparing patients with thyroid dysfunction with that expected in the general population. Results We included 163,972 patients, of which 92,783 had hyperthyroidism and 71,189 had hypothyroidism. In general, we found an increased risk of all gastrointestinal cancers within the first year after thyroid disease diagnosis. After more than 5 years of follow-up, patients with hyperthyroidism had a slightly increased risk of pancreatic and gallbladder and biliary tract cancer. Patients with hypothyroidism had a slightly increased risk of stomach, anal, liver, gallbladder and biliary tract, and pancreatic cancer after more than 5 years of follow-up, but the observed numbers of cancers were in general similar to the expected. Conclusions The increased risks of all gastrointestinal cancers in the first year following hyper- or hypothyroidism diagnosis are likely due to detection bias. After more than 5 years of follow-up, there does not seem to be a consistent causal association between thyroid disease and gastrointestinal cancer.

Aims Some antipsychotics increase prolactin levels, which might increase the risk of breast cancer. Existing evidence is conflicting and based on sparse data, especially for the increasingly used second-generation antipsychotics. We conducted a nationwide case-control study of the association between antipsychotic use and incident breast cancer. Methods From the Danish Cancer Registry, we identified women with a first-time diagnosis of breast cancer 2000-2015 (n = 60 360). For each case, we age-matched 10 female population controls. Using conditional logistic regression, we calculated odds ratios (ORs) for breast cancer associated with use of antipsychotics. We stratified antipsychotics by first- and second-generation status and by ability to induce elevation of prolactin. Results In total, 4951 cases (8.1%) and 47 643 controls (7.9%) had ever used antipsychotics. Long-term use (≥10 000 mg olanzapine equivalents) was associated with breast cancer, with an adjusted OR of 1.18 [95% confidence interval (CI), 1.06, 1.32]. A weak dose-response pattern was seen, with ORs increasing to 1.27 (95% CI 1.01, 1.59) for ≥50 000 mg olanzapine equivalents. Associations were similar for first- and second-generation antipsychotics (ORs 1.17 vs. 1.11), but also for nonprolactin inducing-antipsychotics (OR 1.17). Stratifying by oestrogen receptor status, positive associations were seen for oestrogen receptor-positive cancers (long-term use: OR 1.29; 95% CI 1.13, 1.47) while no associations were observed for oestrogen receptor-negative cancers. Conclusions Overall, our results do not suggest a clinically important association between antipsychotic use and risk of breast cancer. The importance of drug-induced prolactin elevation is unclear but may lead to a slightly increased risk of oestrogen receptor-positive breast cancer.

PURPOSE: How a second breast cancer diagnosis affects survival in comparison with unilateral breast cancer (UBC) is unclear. Prognostic factors for contralateral breast cancer (CBC) are also not well established. We aimed to investigate the survival pattern after CBC with particular focus on time between first and second breast cancer diagnosis and age at CBC diagnosis.METHODS: Within the nationwide Danish Breast Cancer Cooperative Group database, we identified 68,466 breast cancer patients diagnosed during 1978-2012. Patients who subsequently developed CBC were identified in a previously established database (N = 3004). Patients were followed for breast cancer-specific death in the Danish Register of Causes of Death until 2015. Hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated using Cox proportional hazard regression models. Cumulative breast cancer mortality from date of CBC was estimated using the Aalen-Johansen method.RESULTS: Compared with UBC patients, the rate of dying from breast cancer was more than twofold higher following a CBC diagnosis, after adjustment for age, period, tumor characteristics, and treatment of the first breast cancer (HR 2.48; 95% CI 2.31-2.66). Short time interval (CONCLUSION: Breast cancer-specific mortality rates were markedly higher after compared with before a CBC diagnosis. We found higher breast cancer-specific mortality after CBC associated with a short interval between diagnoses among patients diagnosed with CBC before age 70 years.

Background Antihypertensives may inhibit pancreatic carcinogenesis. We examined the association between use of these drugs and pancreatic cancer in patients with chronic pancreatitis. Methods We conducted a nationwide population-based cohort study of all chronic pancreatitis patients diagnosed in Denmark during 1996–2012. Using a Cox proportional hazards model with time-varying exposure lagged by 1 year, we examined the risk of pancreatic cancer according to antihypertensive drug use. Results We included 8,311 patients with chronic pancreatitis and observed 153 pancreatic cancers during follow-up. At baseline, 2197 patients (26.4%) were exposed to at least one class of antihypertensive drugs. We did not observe any measurable associations between the use of antihypertensive drugs and pancreatic cancer. Conclusions Our findings suggest little evidence of an association between the use of antihypertensive drugs and pancreatic cancer risk in patients with chronic pancreatitis. Confirmation is warranted in future studies.

Deirdre Cronin-Fenton Department of Clinical Epidemiology, Aarhus University, Aarhus N, DenmarkThis editorial comments on the paper “Hot green tea drinking increases esophageal squamous cell carcinoma risk in a high-risk area of China: a population-based case–control study”.8

Background: Breast cancer patients have a lifelong 2–4-fold increased risk of developing a second primary tumor in the contralateral breast compared with the risk for a first primary breast cancer in the general female population. Prevention of contralateral breast cancer (CBC) has received increased attention during recent decades. Here, we summarize and discuss the available literature on drug preventive therapy and CBC. Results: The endocrine-targetting drugs, tamoxifen and aromatase inhibitors are used as standard adjuvant treatment for estrogen receptor (ER)-positive breast cancer. Both are associated with relative risk reductions of CBC of up to 50%, but incur serious side effects. Several prescription drugs originally developed for other purposes, including bisphosphonates, statins, non-steroidal anti-inflammatory drugs, metformin, anti-hypertensives and retinoids, have shown anti-cancer activity in preclinical models. However, results of observational studies on CBC are sparse and inconsistent, with only statins demonstrating promise as preventive agents and a potential treatment option for ER-negative breast cancer patients. Conclusion: Future studies are needed to assess the effect of statins in risk reduction and to identify other drugs with chemopreventive potential against CBC. Eventually, efforts must be directed towards identifying those breast cancer patients likely to benefit most from specific preventive therapies.

BACKGROUND: To identify demographic characteristics, comorbidities, medical procedures, and prescription drug use that may act as predictors of underlying pancreatic cancer in acute pancreatitis.METHODS: A cohort study of all patients admitted to Danish hospitals with incident acute pancreatitis during 1999-2015. The ability of age, sex, selected comorbidities, medical procedures, and prescription drug use to predict underlying pancreatic cancer in acute pancreatitis (i.e., pancreatic cancer diagnosed up to one year after acute pancreatitis) was examined. The absolute risk and odds ratio (OR) with 95% confidence interval (CI) of cancer was computed for each variable.RESULTS: 28,231 patients with incident acute pancreatitis, of which 283 (1.0%) had underlying pancreatic cancer, were included. Age >50 years was a predictor of pancreatic cancer with highest risk in patients aged 56-70 years. New-onset chronic pancreatitis (multivariable OR: 2.36 [95% CI: 1.35-4.14]) and new-onset diabetes (multivariable OR: 1.94 [95% CI: 1.30-2.92]) were also predictors of pancreatic cancer. Diagnoses of biliary or alcohol-related diseases were predictors of no underlying pancreatic cancer. Most variables examined had no or limited predictive ability.CONCLUSION: Age, new-onset chronic pancreatitis, new-onset diabetes, and absence of biliary or alcohol-related diseases were predictors of underlying pancreatic cancer in acute pancreatitis patients.

PURPOSE Phthalate exposure is ubiquitous and especially high among users of drug products formulated with phthalates. Some phthalates mimic estradiol and may promote breast cancer. Existing epidemiologic studies on this topic are small, mostly not prospective, and have given inconsistent results. We estimated associations between longitudinal phthalate exposures and breast cancer risk in a Danish nationwide cohort, using redeemed prescriptions for phthalate-containing drug products to measure exposure. METHODS We ascertained the phthalate content of drugs marketed in Denmark using an internal Danish Medicines Agency ingredient database. We enrolled a Danish nationwide cohort of 1.12 million women at risk for a first cancer diagnosis on January 1, 2005. By combining drug ingredient data with the Danish National Prescription registry, we characterized annual, cumulative phthalate exposure through redeemed prescriptions. We then fit multivariable Cox regression models to estimate associations between phthalate exposures and incident invasive breast carcinoma according to tumor estrogen receptor status. RESULTS Over 9.99 million woman-years of follow-up, most phthalate exposures were not associated with breast cancer incidence. High-level dibutyl phthalate exposure (≥ 10,000 cumulative mg) was associated with an approximately two-fold increase in the rate of estrogen receptor–positive breast cancer (hazard ratio, 1.9; 95% CI, 1.1 to 3.5), consistent with in vitro evidence for an estrogenic effect of this compound. Lower levels of dibutyl phthalate exposure were not associated with breast cancer incidence. CONCLUSION Our results suggest that women should avoid high-level exposure to dibutyl phthalate, such as through long-term treatment with pharmaceuticals formulated with dibutyl phthalate.

Background Hypothyroidism may occur as a late effect of breast cancer-directed treatment, particularly after radiotherapy, but little is known whether hypothyroidism affects the prognosis after breast cancer. We investigated the association between hypothyroidism and breast cancer recurrence, and all-cause mortality. Methods In this population-based cohort study, we used national medical registries to identify all Danish women 35 years or older diagnosed with stage I–III, operable breast cancer between 1996 and 2009. Hypothyroidism was defined as hospital diagnoses ascertained via diagnostic codes, or as prescriptions for levothyroxine. Two analytic models were used: (i) hypothyroidism present at the time of the breast cancer diagnosis (prevalent) and (ii) hypothyroidism diagnosed during follow-up as a time-varying exposure lagged by 1 year (incident). Breast cancer recurrence was defined as any local, regional, or distant recurrence or contralateral breast cancer. All-cause mortality included death from any cause in any setting. We used Cox regression models accounting for competing risks to compute adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) of breast cancer recurrence and all-cause mortality. Results The study cohort included 35,463 women with breast cancer with 212,641 person-years of follow-up. At diagnosis, 1272 women had hypothyroidism and 859 women developed hypothyroidism during follow-up. In total, 5810 patients developed recurrent breast cancer. Neither prevalent nor incident hypothyroidism was associated with breast cancer recurrence (adjusted HRprevalent 1.01, 95% CI 0.87–1.19; adjusted HRincident 0.93, 95% CI 0.75–1.16, respectively). Furthermore, no differences were seen for all-cause mortality for prevalent or incident hypothyroidism (adjusted HRprevalent 1.02, 95% CI 0.92–1.14, and HRincident 1.08, 95% CI 0.95–1.23, respectively). Stratification by menopausal status, oestrogen receptor status, chemotherapy, or radiotherapy did not alter the estimates. Conclusions Hypothyroidism present at diagnosis or during follow-up was not associated with breast cancer recurrence or all-cause mortality in women with breast cancer. Our findings provide reassurance to patients and their physicians that hypothyroidism is unlikely to impact on the clinical course of breast cancer or survival. Electronic supplementary material The online version of this article (10.1186/s13058-019-1122-3) contains supplementary material, which is available to authorized users.

Background: Adjuvant tamoxifen therapy approximately halves the risk of recurrence in estrogen receptor-positive (ER+) breast cancer patients, but many women respond insufficiently to therapy. Expression of multi-drug resistance protein 2 (MRP2) in breast cancer may potentiate tamoxifen resistance. Thus, we investigated the expression of MRP2 in breast cancer as a predictor of tamoxifen therapy effectiveness. Material and methods: We conducted a case-control study nested in the Danish Breast Cancer Group clinical database. The study included women aged 35–69 years diagnosed with stage l–lll breast cancer during 1985–2001, in Jutland, Denmark. We identified 541 recurrent breast cancers (cases) among women with estrogen receptor positive (ER+) disease treated with tamoxifen for at least 1 year (ER+/TAM+) and 300 cases among women with estrogen receptor-negative (ER−) disease, never treated with tamoxifen (ER−/TAM−). We matched one recurrence-free control to each recurrent case. We retrieved paraffin-embedded primary tumor tissue for all patients, and all available recurrent tumor tissue from pathology archives. MRP2 expression was evaluated using immunohistochemistry. We computed odds ratios (ORs) and 95% confidence intervals (95% CIs) associating MRP2 expression (positive vs. none) with breast cancer recurrence in conditional logistic regression models. We compared MRP2 expression in paired primary- and recurrent tumors. Results: MRP2 expression was more prevalent in the ER+/TAM + group, than in the ER−/TAM − group. No predictive utility of MRP2 for breast cancer recurrence was found in the ER+/TAM + group (ORadj = 0.96, 95% CI 0.70, 1.33). Further, no prognostic utility was found in the ER−/TAM − group (ORadj = 0.81, 95% CI 0.53, 1.23). MRP2 expression was not increased in recurrent versus primary tumors. Conclusions: MRP2 expression is neither a predictive marker of tamoxifen effectiveness nor a prognostic marker in breast cancer.

BACKGROUND: Survivin is an inhibitor of apoptosis, and its expression associates with poor outcomes in multiple cancers. It may be a therapeutic target due to its unique expression in cancer cells.METHODS: We estimated the association between nuclear and cytoplasmic survivin expression in primary tumors and breast cancer recurrence. In this case-control study, we included women age 35-69, diagnosed with stage I-III breast cancer between 1985 and 2001, and registered with the Danish Breast Cancer Group. We identified 541 patients with breast cancer recurrence with estrogen receptor-positive disease who were treated with tamoxifen for at least 1 year (ER+/TAM+) and 300 with estrogen receptor-negative carcinomas, not treated with tamoxifen, and who survived at least 1 year (ER-/TAM-). Controls were matched to cases on ER/TAM status, date of surgery, menopausal status, stage and county. Survivin expression was estimated by immunohistochemistry on tissue microarrays. We fit logistic regression models to estimate odds ratios (ORs) and 95% confidence intervals (CIs) associating nuclear and cytoplasmic survivin expression with recurrence.RESULTS: Associations between nuclear and cytoplasmic survivin expression and breast cancer recurrence were near-null in both ER+/TAM + and ER-/TAM - strata. For the cytoplasmic to nuclear ratio (CNR) of survivin expression, we found a null association in the ER+/TAM + group comparing CNR ≥5 with CNR CONCLUSIONS: Survivin expression was not associated with breast cancer recurrence in this study. The CNR ratio may warrant further investigation especially among ER - tumors.

Clinical trials are considered the gold standard for examining drug efficacy and for approval of new drugs. Medical databases and population surveillance registries are valuable resources for post-approval observational research, which are increasingly used in studies of benefits and risk of new cancer drugs. Here, we address the challenges in translating endpoints from oncology trials to observational studies. Registry-based cohort studies can investigate real-world safety issues - including previously unrecognized concerns - by examining rare endpoints or multiple endpoints at once. In contrast to clinical trials, observational cohort studies typically do not exclude real-world patients from clinical practice, such as old and frail patients with comorbidity. The observational cohort study complements the clinical trial by examining the effectiveness of interventions applied in clinical practice and by providing evidence on long-term clinical outcomes, which are often not feasible to study in a clinical trial. Various endpoints can be included in clinical trials, such as hard endpoints, soft endpoints, surrogate endpoints, and patient-reported endpoints. Each endpoint has it strengths and limitations for use in research studies. Endpoints used in oncology trials are often not applicable in observational cohort studies which are limited by the setting of standard clinical practice and by non-standardized endpoint determination. Observational studies can be more helpful moving research forward if they restrict focus to appropriate and valid endpoints.

PURPOSE: Adjuvant chemotherapy has been associated with loss of bone mineral density (BMD) either as a direct effect or due to glucocorticoids used as supportive care medication. A prospective cohort study was conducted to evaluate changes in BMD from baseline to right after completion of chemotherapy, i.e., 4 months.METHODS: Dual-imaging X-ray absorptiometry (DXA) was performed at baseline and after completing anthracycline- and taxane-based chemotherapy to measure BMD in the spine, hip, and forearm in early-stage breast cancer patients. High-dose prednisolone was used at three weekly intervals to reduce nausea and vomiting. Patients were advised a daily calcium/vitamin D supplement. Linear regression was used to assess mean percentage change in BMD and 95 % confidence intervals (95 % CI) according to doses of prednisolone, menopausal status, smoking, and BMI.RESULTS: Eight patients were excluded: seven because of initiation of bisphosphonate treatment due to osteoporosis at baseline, and one had non-interpretable DXA. The final cohort included 97 patients with a mean age of 53 years (range 34-72). Mean cumulative prednisolone dose was 1308 mg (95 % CI 1255; 1362). BMD increased 1.36 % (95 % CI 0.7; 2.0, p CONCLUSIONS: Adjuvant chemotherapy supplemented with prednisolone was not associated with loss of BMD. Postmenopausal women gained bone mass, whereas current smokers lost bone mass.

Observational studies of aspirin use and breast cancer risk have provided inconsistent results. The occurrence of contralateral breast cancer (CBC) among breast cancer survivors may serve as a useful high-risk model to identify preventive drug effects. Using this model, we examined the association between post-diagnosis use of low-dose aspirin and risk of CBC. We identified all women recorded with a first primary breast cancer in the Danish Breast Cancer Cooperative Group Database between 1996 and 2012. Information on drug use, tumor and patient characteristics, treatment, and CBC was obtained from nationwide registries. In the main analysis, we defined time-varying post-diagnosis low-dose aspirin use as two or more prescriptions filled during follow-up and applied a one-year exposure lag. Cox proportional hazard regression models were used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs) for the association between post-diagnosis low-dose aspirin use and CBC risk. Among 52,723 breast cancer patients, 1,444 women developed CBC during a median follow-up of 4.8 years. The adjusted HR for CBC associated with post-diagnosis use of low-dose aspirin was 0.91 (95% CI: 0.75-1.09). We observed no substantial variation in HRs according to pattern of low-dose aspirin use or estrogen receptor status of the first or the contralateral breast cancer. In conclusion, this large nationwide cohort study of breast cancer survivors does not provide strong evidence suggesting an association between post-diagnosis use of low-dose aspirin and risk of CBC.

Stine Bakkensen Bruun,1 Irene Petersen,1,2 Nickolaj Risbo Kristensen,1 Deirdre Cronin-Fenton,1 Alma Becic Pedersen1 1Department of Clinical Epidemiology, Aarhus University Hospital, Aarhus, Denmark; 2Department of Primary Care and Population Health, University College London, London, UK Purpose: To examine the association between selective serotonin reuptake inhibitor (SSRI) use and mortality, postoperative complications, and quality of in-hospital care in hip fracture patients. Patients and methods: The study was a nationwide cohort study based on individual-level linked, prospectively collected data from Danish population-based national registries covering all hospitals in Denmark. The health care system in Denmark is tax-funded, and all citizens have equal access to health care services. We included patients with first-time hospitalization due to hip fracture undergoing surgery from 2006–2016. We estimated the risk of 30-day mortality, any unplanned readmission, any reoperation, specific postoperative complications including cardiovascular events and major bleeding, and quality of in-hospital care using Cox and Poisson regression analyses comparing current and former SSRI users with non-users. Results: In 68,487 hip fracture patients, 13,272 (19%) were current SSRI users, 2,777 (4%) were former SSRI users, and 52,438 (77%) were SSRI non-users. The 30-day mortality risk was 13% in current SSRI users (HR 1.16, 1.10–1.21) and 12% in former (HR 1.15, 1.04–1.27) compared with 10% in non-users. The HR for any unplanned readmission was 1.11 (1.02–1.20) in current and 1.13 (1.01–1.27) in former SSRI users and for any reoperation 1.21 (1.11–1.31) in current and 1.04 (0.84–1.28) in former SSRI users compared with non-users. The risk of venous thromboembolism, myocardial infarction, stroke, and bleeding were similar irrespective of SSRI use. No association between current and former SSRI use and quality of in-hospital care was found. Conclusion: In patients undergoing hip fracture surgery, 30-day mortality and overall readmission risk were elevated in both current and former SSRI users compared with non-users. Those currently using SSRI had a 26% increased reoperation risk compared with non-users. However, SSRI use was not associated with increased risk of other postoperative complications and lower quality of in-hospital care. A limitation of this study was the inability to control for potential confounding of social deprivation. Keywords: cohort studies, hip fracture, mortality, postoperative complications, quality of care, selective serotonin reuptake inhibitors