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In advanced HER2-positive (HER2+) breast cancer, the new antibody-drug conjugate trastuzumab deruxtecan is more effective compared with trastuzumab emtansine (T-DM1). However, trastuzumab deruxtecan can have considerable toxicities, and the right treatment sequence is unknown. Biomarkers to guide the use of anti-HER2 therapies beyond HER2 status are needed. Here, we evaluated if preestablished levels of ERBB2 mRNA expression according to the HER2DX standardized assay are associated with response and survival following T-DM1. In ERBB2 low, medium, and high groups, the overall response rate was 0%, 29%, and 56%, respectively (P

Purpose:The role of immunotherapy in hormone receptor (HR)-positive, HER2-negative breast cancer is underexplored.Patients and Methods:The neoadjuvant phase II GIADA trial (NCT04659551, EUDRACT 2016-004665-10) enrolled stage II–IIIA premenopausal patients with Luminal B (LumB)-like breast cancer (HR-positive/HER2-negative, Ki67 ≥ 20%, and/or histologic grade 3). Patients received: three 21-day cycles of epirubicin/cyclophosphamide followed by eight 14-day cycles of nivolumab, triptorelin started concomitantly to chemotherapy, and exemestane started concomitantly to nivolumab. Primary endpoint was pathologic complete response (pCR; ypT0/is, ypN0).Results:A pCR was achieved by 7/43 patients [16.3%; 95% confidence interval (CI), 7.4–34.9]; the rate of residual cancer burden class 0–I was 25.6%. pCR rate was significantly higher for patients with PAM50 Basal breast cancer (4/8, 50%) as compared with other subtypes (LumA 9.1%; LumB 8.3%; P = 0.017). Tumor-infiltrating lymphocytes (TIL), immune-related gene-expression signatures, and specific immune cell subpopulations by multiplex immunofluorescence were significantly associated with pCR. A combined score of Basal subtype and TILs had an AUC of 0.95 (95% CI, 0.89–1.00) for pCR prediction. According to multiplex immunofluorescence, a switch to a more immune-activated tumor microenvironment occurred following exposure to anthracyclines. Most common grade ≥3 treatment-related adverse events (AE) during nivolumab were γ-glutamyltransferase (16.7%), alanine aminotransferase (16.7%), and aspartate aminotransferase (9.5%) increase. Most common immune-related AEs were endocrinopathies (all grades 1–2; including adrenal insufficiency, n = 1).Conclusions:Luminal B-like breast cancers with a Basal molecular subtype and/or a state of immune activation may respond to sequential anthracyclines and anti–PD-1. Our data generate hypotheses that, if validated, could guide immunotherapy development in this context.

Supplementary Data from Neoadjuvant Chemotherapy and Immunotherapy in Luminal B-like Breast Cancer: Results of the Phase II GIADA Trial

IntroductionPatients with triple-negative breast cancer (TNBC) achieving a pathological complete response (pCR) after neoadjuvant chemotherapy have a better event-free survival. The role of gut microbiome in early TNBC is underexplored.MethodsMicrobiome was analyzed by 16SrRNA sequencing.ResultsTwenty-five patients with TNBC treated with neoadjuvant anthracycline/taxane-based chemotherapy were included. Fifty-six percent achieved a pCR. Fecal samples were collected before (t0), at 1 (t1), and 8 weeks (t2) from chemotherapy. Overall, 68/75 samples (90.7%) were suitable for microbiome analysis. At t0, pCR group showed a significantly higher α-diversity as compared with no-pCR, (P = .049). The PERMANOVA test on β-diversity highlighted a significant difference in terms of BMI (P = 0.039). Among patients with available matched samples at t0 and t1, no significant variation in microbiome composition was reported over time.ConclusionsFecal microbiome analysis in early TNBC is feasible and deserves further investigation in order to unravel its complex correlation with immunity and cancer.

Background: Recent evidences showed intestinal microbiota to be implicated in carcinogenesis and response to chemotherapy and immune checkpoint inhibitors in solid tumors. Furthermore, antibiotics are known to deeply influence microbiome composition in healthy people and cancer patients. The role of gut microbiome in triple negative breast cancer (TNBC) is underexplored. Methods: In this pilot prospective study, we characterized the gut microbiome of 30 TNBC patients undergoing neoadjuvant chemotherapy at two Italian Institutions. Fecal samples were collected at 2 timepoints: at the baseline (t0) and at 1 week (t1) from CT. Microbiome was analyzed by 16S rRNA sequencing. Measures of α-diversity expressed by Richness and Simpson evenness were evaluated at the species level. β-diversity was calculated using PERMANOVA test according to UniFrac measures of dissimilarity at the species level.Tumor infiltrating lymphocytes (TILs) were assessed from diagnostic core biopsy and surgical specimen. Results: From September 2017 to March 2020, 30 TNBC patients were enrolled. Median age was 53 years, 43% were premenopausal, 43% were overweight or obese (BMI>25); 97% had a histologic G3 carcinoma, clinical nodal involvements was present in 57%; median TILs at diagnosis was 30%. All patients received anthracycline and taxane-based chemotherapy, including carboplatin in 23 patients (77%). A pCR was achieved in 15 (50%) patients. The overall rate of stool samples collection was 93%. With regards to t0, no differences in terms of α- and β-diversity were found.At t1, α-diversity was significantly higher in pCR group (Simpson evenness index, p=0.016). Considering clinical-pathological features, a BMI 90 days after the end of antibiotic therapy (N=17). At this analysis, β-diversity evaluated with Unifrac measure was significantly correlated with pCR (p=0.035), with Haemophilus Influentiae being significantly enriched in non-pCR group. Conclusions: Fecal microbiome collection and analysis in this population is feasible and deserves further investigation with regards its association with response to chemotherapy. Citation Format: Grazia Maria Vernaci, Davide Massa, Ilaria Patuzzi, Alice Menichetti, Tommaso Giarratano, Gaia Griguolo, Federica Miglietta, Matteo Fassan, Edoardo Savarino, PierFranco Conte, Valentina Guarneri, Maria Vittoria Dieci. Characterization of gut microbiome composition in triple negative breast cancer patients treated with neoadjuvant chemotherapy [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 P2-12-04.

Purpose: The role of immunotherapy in hormone receptor (HR)-positive, HER2-negative breast cancer is underexplored. Patients and Methods: The neoadjuvant phase II GIADA trial (NCT04659551, EUDRACT 2016-004665-10) enrolled stage II–IIIA premenopausal patients with Luminal B (LumB)-like breast cancer (HR-positive/HER2-negative, Ki67 ≥ 20%, and/or histologic grade 3). Patients received: three 21-day cycles of epirubicin/cyclophosphamide followed by eight 14-day cycles of nivolumab, triptorelin started concomitantly to chemotherapy, and exemestane started concomitantly to nivolumab. Primary endpoint was pathologic complete response (pCR; ypT0/is, ypN0). Results: A pCR was achieved by 7/43 patients [16.3%; 95% confidence interval (CI), 7.4–34.9]; the rate of residual cancer burden class 0–I was 25.6%. pCR rate was significantly higher for patients with PAM50 Basal breast cancer (4/8, 50%) as compared with other subtypes (LumA 9.1%; LumB 8.3%; P = 0.017). Tumor-infiltrating lymphocytes (TIL), immune-related gene-expression signatures, and specific immune cell subpopulations by multiplex immunofluorescence were significantly associated with pCR. A combined score of Basal subtype and TILs had an AUC of 0.95 (95% CI, 0.89–1.00) for pCR prediction. According to multiplex immunofluorescence, a switch to a more immune-activated tumor microenvironment occurred following exposure to anthracyclines. Most common grade ≥3 treatment-related adverse events (AE) during nivolumab were γ-glutamyltransferase (16.7%), alanine aminotransferase (16.7%), and aspartate aminotransferase (9.5%) increase. Most common immune-related AEs were endocrinopathies (all grades 1–2; including adrenal insufficiency, n = 1). Conclusions: Luminal B-like breast cancers with a Basal molecular subtype and/or a state of immune activation may respond to sequential anthracyclines and anti–PD-1. Our data generate hypotheses that, if validated, could guide immunotherapy development in this context.

Background: Hormone-receptor (HR)+/HER2- breast cancer (BC) is a biologically heterogeneous disease. Homologous recombination deficiency (HRD) and BRCA mutations have been previously reported to be associated with worse outcomes in HR+/HER2- metastatic BC patients receiving CDK4/6 inhibitors and endocrine therapy. Here, we assess the relation between HRD and RB-loss signatures, intrinsic subtyping, the PAM50-based chemo-endocrine score, and response to chemotherapy-based therapy and endocrine treatment in HR+/HER2- early BC. Methods: GIADA is a multicentric neoadjuvant phase II trial that treated premenopausal patients with Luminal B (LumB)-like BC (HR-positive, HER2-negative, with Ki67>20% and/or histologic Grade 3) with a combination of chemotherapy, immunotherapy and endocrine treatment. Expression of 758 genes on baseline tumor samples from all 43 patients was quantified by nCounter platform. The LETLOB phase II trial randomized postmenopausal women with clinical stage II-IIIA HR+/HER2- BC to neoadjuvant letrozole + lapatinib or letrozole + placebo for 6 months (Guarneri, JCO 2014). Gene-expression data (Affymetrix platform) from pre-treatment frozen core-biopsies was available from 66 out of 92 pts enrolled. Intrinsic subtype was assigned using a research-based PAM50 subtype predictor. A published HRD signature (Peng, Nat Commun 2014) and a signature of RB loss (RBsig), previously reported to potentially predict resistance to CDK4/6 inhibitors in HR+/HER2- BC (Malorni, Oncotarget 2016) were computed. The PAM50 based chemo-endocrine score (CES) was calculated using published definition (Prat, CCR 2017). Higher values of CES indicate increased endocrine sensitivity, while lower values indicate chemosensitivity. Association between genomic signatures was assessed through Pearson’s correlation coefficient. Association of genomic signatures with pCR was assessed through logistic regression and association with PEPI scores was assessed through Kruskal-Wallis test. Results: HRD signature levels were significantly higher in non-luminal (Basal-like and HER2-enriched) tumors as compared to Luminal (A or B) tumors (p>0.001 in the GIADA trial, p=0.021 in the LETLOB trial). Moreover, higher levels of HRD signature were associated with higher levels of RB-loss signature (Pearson correlation 0.355, p=0.020 in the GIADA trial; Pearson correlation 0.942, p< 0.001 in the LETLOB trial), higher levels of Basal-like signature (Pearson correlation 0.502, p< 0.001 in the GIADA trial; Pearson correlation 0.373, p=0.002 in the LETLOB trial) and lower levels of CES (Pearson correlation -0.422, p=0.005 in the GIADA trial; Pearson correlation -0.763, p< 0.001 in the LETLOB trial), indicative of higher chemosensitivity. In the GIADA trial, higher levels of HRD signature (p=0.018) and RBloss signature (p=0.073) and lower levels of CES (p=0.007) were associated with higher pCR rates after chemo, endocrine and immunotherapy. In the LETLOB trial, lower levels of HRD signature (p=0.068) and RBloss signature (p=0.042) and higher levels of CES (p=0.050) were associated with higher sensitivity to endocrine treatment (lower PEPI scores, 0 vs 1-3 vs 4 or more, after neoadjuvant letrozole). Conclusions: In HR+/HER2- early BC, HRD gene signatures, RB-loss gene signatures and non-luminal (especially Basal-like) intrinsic subtyping are associated with each other and associated with higher sensitivity to chemotherapy-based therapy and lower sensitivity to endocrine treatment. These observations might help correctly tailor systemic therapy, including biologic agents, in patients with HR+/HER2- early and advanced BC. Citation Format: Gaia Griguolo, Federica Miglietta, Laia Paré, Daniele G. Generali, Antonio Frassoldati, Antonino Musolino, Simon Spazzapan, Grazia Vernaci, Tommaso Giarratano, Marcello Lo Mele, Giancarlo Bisagni, Federico Piacentini, Enrico Tagliafico, Katia Cagossi, Francesca Schiavi, Claudia Pinato, Aleix Prat, Valentina Guarneri, Maria Vittoria Dieci. Homologous recombination deficiency, RB-loss gene signatures, intrinsic subtype and response to neoadjuvant treatment in HR+/HER2- early breast cancer: a correlative analysis of two phase II trials [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 P4-02-13.

The impact of the COVID19 pandemic on treatment practices for patients diagnosed with early breast cancer: a cross-sectional study from a large comprehensive cancer centre in Italy. Introduction: The Coronavirus Disease 2019 (COVID19) has disrupted health services worldwide. The evidence on the impact of the pandemic on cancer care provision, however, is conflicting. Some reports found that management for patients diagnosed with early breast cancer (EBC) during the pandemic did not differ from pre-pandemic practices; other reports suggested that delays in breast cancer surgery may have occurred. We aimed to audit the management of patients diagnosed with EBC during the pandemic in a large, tertiary-level cancer centre in Italy. Methods: We conducted a cross-sectional study to track the route to first treatment for patients diagnosed with EBC during 2019, 2020, and 2021. We abstracted data for all consecutive patients referred to the Veneto Institute of Oncology (Padua, Italy). We defined as point of contact (POC) the date of the first consultation with a breast cancer specialist of the breast unit. We considered patients with a first POC in the 6 months preceding the multidisciplinary (MDT) meeting and initiating a treatment within 6 months from the POC. We chose the 3-month period April-June because in 2020 it was when health services were first acutely disrupted. We analysed the same period for 2019 and 2021. First treatment was defined as either upfront surgery or neoadjuvant chemotherapy (NACT). The time to first treatment was defined as the interval between the first POC and the first treatment. We used the median time to first treatment in 2019 to define the threshold for treatment delay. Results: We reviewed medical records for 878 patients for whom an MDT report during 2019-2021 (April through June) was available. Of these, 431 (49%) were eligible: 144 in 2019, 127 in 2020 and 150 in 2021. Median age at first POC was 61 years. The proportion of screen-detected tumours was larger in 2019 and 2021 than in 2020 (59%). Conversely, the proportion of screen-detected tumours was offset by the proportion of palpable tumours in 2020 (44% versus 56%). These differences were statistically significant (chi-square test 11.12, p=0.004). Distribution of tumour and nodal stage was unchanged over time, but in-situ tumours were slightly fewer in 2020 than in 2019 or 2021. The odds ratio for treatment delay (45 days or more) was 0.87 for 2020 versus 2019 (95% CI, 0.5-1.53) and 0.9 for 2021 versus 2019 (95% CI, 0.52-1.55), after adjusting for type of POC, presentation with symptoms, treatment type, tumour stage, nodal stage, and EBC subtype (i.e., luminal, HER2-positive, triple-negative). Conclusions: There was no evidence for major changes in the management of EBC patients during 2019-2021 and no treatment delays were observed. However, our results show a slight decrease in the absolute number of patients being treated in 2020, offset by an increase in 2021 to levels comparable to 2019. Our findings suggest that disruption of breast cancer screening programmes may have impacted on the characteristics of the patient population, with a larger proportion of women presenting with palpable nodules. Validation on a larger, population-based cohort of patients is warranted to robustly assess the impact of the COVID19 pandemic on treatment practices and outcome for EBC patients. Characteristics of the population Citation Format: Fabio Girardi, Sabrina Marini, Francesca Porra, Ilaria Mietto, Sonia Carpentieri, Alberto Marchet, Tania Saibene, Marcello Lo Mele, Tommaso Giarratano, Carlo Alberto Giorgi, Eleonora Mioranza, Cristina Falci, Giovanni Faggioni, Francesca Caumo, Gaia Griguolo, Maria Vittoria Dieci, Valentina Guarneri. The impact of the COVID19 pandemic on treatment practices for patients diagnosed with early breast cancer: a cross-sectional study from a large comprehensive cancer centre in Italy. [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 P3-03-01.

Cyclin-dependent kinase 4/6 inhibitors (CDK4/6i) combined with endocrine therapy (ET) are now a backbone of treatment for hormone receptor-positive/human epidermal growth factor receptor 2 (HER2)-negative advanced breast cancer. CDK4/6i plus ET is more effective than ET alone in this setting; however, the risk of grade 3-4 adverse events also increases. Approved agents in this class have similar efficacies, but important differences due to their structural and pharmacological properties. We review biomarkers and discuss determinants to inform a rational approach to therapy choice when selecting the most appropriate ET and CDK4/6i partners. We also identify subgroups that may benefit from specific ET-CDK4/6i combinations and discuss strategies to overcome resistance. This personalized approach aims to minimize treatment-related toxicities that may affect patient QoL and compliance, and ultimately therapy efficacy.

About a half of HER2-negative breast cancer (BC) show HER2-low expression that can be targeted by new antibody-drug conjugates. The main aim of this study is to describe the evolution of HER2 expression from primary BC to relapse by including HER2-low category in both primary and recurrent BC samples. Patients with matched primary and relapse BC samples were included. HER2 was evaluated according to ASCO/CAP recommendations in place at the time of diagnosis. A cutoff of10% cells staining for HER2-positivity was applied. HER2-negative cases were sub-classified as HER2-low (IHC = 1 + /2+ and ISH not amplified), or HER2-0 (IHC-0). 547 patients were included. The proportion of HER2-low cases was 34.2% on the primary tumor and 37.3% on the relapse samples. Among HER2-negative cases, HER2-low status was more frequent in HR-positive vs triple-negative tumors (47.3% vs 35.4% on primary tumor samples, 53.8% vs 36.2% on relapse samples). The overall rate of HER2 discordance was 38.0%, mostly represented by HER2-0 switching to HER2-low (15%) and HER2-low switching to HER2-0 (14%). Among patients with a primary HER2-negative tumor, the rate of HER2 discordance was higher in HR-positive/HER2-negative vs triple-negative cases (45.5% vs 36.7% p = 0.170). This difference was mostly driven by cases switching from HER2-0 to HER2-low. HER2-low expression is highly unstable during disease evolution. Relapse biopsy in case of a primary HER2-0 tumor may open new therapeutic opportunities in a relevant proportion of patients.

Background: In the last decades, long-term outcomes of breast cancer (BC) patients have improved, raising new survivorship issues, including fertility preservation and safety of pregnancy after BC. This study assesses evolution in patterns of fertility discussion/preservation over time and reports pregnancy outcomes in a cohort of young BC patients. Methods: A retrospective cohort of 590 BC patients aged ≤40 diagnosed between 2000 and 2016 at a large cancer center was identified. Fertility counseling and preservation patterns for patients receiving chemotherapy were analyzed and compared for two cohorts: 2004–2006 and 2014–2016 (total n = 161). Outcomes were reported for patients with documented pregnancy after BC. Results: Significantly, more patients diagnosed in 2014–2016 had evidence of discussion on fertility issues and/or application of fertility preservation techniques versus patients diagnosed in 2004–2006 (82.9% vs. 66.0%, p = 0.017). In particular, there was a significant difference in rate of documented fertility issues discussion (67.6% vs. 34.0%, p 35 and parity were associated with lower rates of fertility discussion/preservation. However, rates significantly improved over time (77.6% in 2014–2016 vs. 58.1% in 2004–2006 for patients aged >35, p = 0.046; 80.7% in 2014–2016 vs. 57.6% in 2004–2006 for patients with children at diagnosis, p = 0.018). Twenty-six patients with pregnancy after BC were identified; eight delivered at the age of >40. No complications for women or newborns were reported. Only two patients experienced BC relapse. Conclusions: In this small retrospective cohort, no safety concerns were identified for pregnancy after BC. The importance attributed by clinicians to address fertility issues has increased over time.

Background: Trastuzumab + pertuzumab + taxane and ado-trastuzumab emtansine (T-DM1) are standard first and second-line therapies for HER2+ metastatic breast cancer. Lapatinib is approved in combination with capecitabine in trastuzumab-resistant patients and in combination with letrozole in hormone receptor positive HER2+ pts for whom endocrine treatment is indicated. In Italy, L is also approved in combination with trastuzumab for hormone receptor-negative HER2+ pts. There are only few data on the activity of lapatinib in pts who received prior pertuzumab and /or T-DM1. Methods: We retrospectively analysed HER2+ metastatic breast cancer pts who received lapatinib after prior pertuzumab and/or T-DM1 from July 2013 to June 2018. Objective response rate (ORR) was assessed according to RECIST 1.1. Progression-free survival (PFS) was calculated from lapatinib-based therapy starting to disease progression (PD) or last follow-up. Overall Survival (OS) was calculated from lapatinib-based therapy starting to death or last follow up. Results: Data from 32 HER2+ mBC treated with lapatinib-based therapy were recorded: 30 pts (94%) received lapatinib combined with capecitabine, 1 pt received lapatinib combined with letrozole and 1 pt received lapatinib combined with trastuzumab. All patients had been treated with prior T-DM1 and 9 (28%) with prior pertuzumab for metastatic breast cancer. Setting of treatment with lapatinib-based therapy was: 2° line (n=2, 6%), 3° line (n=17, 53%) and >4° line (n=13, 41%). Patients characteristics were as follows: median age 55 years (range 35-71), hormone receptor positive 66% (n=21), stage IV at diagnosis 34% (n=11), visceral involvement at lapatinib-based therapy starting 91% (n=29). As of June 2018, lapatinib-based therapy was ongoing for 4 pts and 28 pts discontinued treatment due to disease progression (median number of courses for these pts was 8.5, range 2-27). ORR in evaluable pts was: complete response (n=1, 3%), partial response (n=13, 41%), stable disease (n=9, 28%), disease progression (n=9, 28%). Median PFS was 6.4 months (95% CI 3.0-9.8). As of June 2018, 14 pts (44%) were alive, median OS was 11.8 months (95% CI 9.9-13.6). Conclusion: These results confirm that lapatinib-based therapy retains clinical efficacy in HER2+ metastatic breast cancer pts treated with prior pertuzumab and/or T-DM1 and represents a valid therapeutic option in this setting. Citation Format: Frezzini S, Giarratano T, Dieci MV, Giorgi CA, Griguolo G, Vernaci G, Menichetti A, Mantiero M, Tasca G, Faggioni G, Falci C, Miglietta F, Mioranza E, Angelini S, Ghiotto C, Conte P, Guarneri V. Lapatinib-based therapies after pertuzumab and/or T-DM1 for HER2+ metastatic breast cancer patients [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P6-18-24.

Background: Real world data have the potential to demonstrate the applicability of the results of randomized studies in the general population. SUPER trial was conducted in order to assess the activity, the efficacy and the safety of the combination of pertuzumab, trastuzumab and chemotherapy in clinical practice.Material and methods: Patients diagnosed with HER2 positive metastatic breast cancer (mBC) and treated with pertuzumab, trastuzumab and chemotherapy were accrued at 18 italian hospitals. Data were retrospectively collected in the time frame between pertuzumab availability in clinical practice and study approval in 2016, and prospectively collected thereafter. Results: Overall 342 HER2 positive mBC were accrued. 172 patients had relapsed disease and 56.4% of them received neo/adjuvant trastuzumab. 205 patients received docetaxel. Objective response rate was 76.3% (95%CI: 71.4–80.7). Median progression free survival (PFS) and overall survival (OS) were 24.3 months (95% CI: 20.0–28.9) and 70.2 months (95% CI: 61.4–79.0) respectively. Triple positive patients treated with endocrine therapy in addition to pertuzumab and trastuzumab maintenance had a significant longer PFS and OS than patients who did not. mPFS was 31.2 months and 13 months respectively (HR=0.47; 95% CI: 0.33–0.66; pConclusions: SUPER suggests that results of first-line treatment with pertuzumab, trastuzumab and chemotherapy in unselected patients are consistent with findings from CLEOPATRA trial.Moreover, as expected from real world evidence, new insights have emerged.

About a half of HER2-negative breast cancer (BC) show HER2-low expression that can be targeted by new antibody-drug conjugates. The main aim of this study is to describe the evolution of HER2 expression from primary BC to relapse by including HER2-low category in both primary and recurrent BC samples. Patients with matched primary and relapse BC samples were included. HER2 was evaluated according to ASCO/CAP recommendations in place at the time of diagnosis. A cutoff of >10% cells staining for HER2-positivity was applied. HER2-negative cases were sub-classified as HER2-low (IHC = 1 + /2+ and ISH not amplified), or HER2-0 (IHC-0). 547 patients were included. The proportion of HER2-low cases was 34.2% on the primary tumor and 37.3% on the relapse samples. Among HER2-negative cases, HER2-low status was more frequent in HR-positive vs triple-negative tumors (47.3% vs 35.4% on primary tumor samples, 53.8% vs 36.2% on relapse samples). The overall rate of HER2 discordance was 38.0%, mostly represented by HER2-0 switching to HER2-low (15%) and HER2-low switching to HER2-0 (14%). Among patients with a primary HER2-negative tumor, the rate of HER2 discordance was higher in HR-positive/HER2-negative vs triple-negative cases (45.5% vs 36.7% p = 0.170). This difference was mostly driven by cases switching from HER2-0 to HER2-low. HER2-low expression is highly unstable during disease evolution. Relapse biopsy in case of a primary HER2-0 tumor may open new therapeutic opportunities in a relevant proportion of patients.

Trastuzumab emtansine (T-DM1) is approved for the treatment of human epidermal growth factor receptor 2 (HER2)-positive (HER2+) metastatic breast cancer (BC) and for residual disease after neoadjuvant therapy, however, not all patients benefit. Here, we hypothesized that the heterogeneity in the response seen in patients is partly explained by the levels of human epidermal growth factor receptor 2 gene (ERBB2) mRNA. We analyzed ERBB2 expression using a clinically applicable assay in formalin-fixed paraffin-embedded (FFPE) tumors (primary or metastatic) from a retrospective series of 77 patients with advanced HER2+ BC treated with T-DM1. The association of ERBB2 levels and response was further validated in 161 baseline tumors from the West German Study (WGS) Group ADAPT phase II trial exploring neoadjuvant T-DM1 and 9 in vitro BC cell lines. Finally, ERBB2 expression was explored in 392 BCs from an in-house dataset, 368 primary BCs from The Cancer Genome Atlas (TCGA) dataset and 10,071 tumors representing 33 cancer types from the PanCancer TCGA dataset. High ERBB2 mRNA was found associated with better response and progression-free survival in the metastatic setting and higher rates of pathological complete response in the neoadjuvant setting. ERBB2 expression also correlated with in vitro response to T-DM1. Finally, our assay identified 0.20&ndash, 8.41% of tumors across 15 cancer types as ERBB2-high, including gastric and esophagus adenocarcinomas, urothelial carcinoma, cervical squamous carcinoma and pancreatic cancer. In particular, we identified high ERBB2 mRNA in a patient with HER2+ advanced gastric cancer who achieved a long-lasting partial response to T-DM1. Our study demonstrates that the heterogeneity in response to T-DM1 is partly explained by ERBB2 levels and provides a clinically applicable assay to be tested in future clinical trials of breast cancer and other cancer types.

Background: Around 20% of breast cancers (BC) are HER-2+. Trastuzumab (T) has dramatically changed the outcome of HER-2+ BC patients (pts), both in early and in advanced settings. The combination of Pertuzumab (P) plus T and docetaxel, used as first-line treatment for HER-2+ metastatic BC (MBC) in the phase III CLEOPATRA study, significantly prolonged progression free survival (PFS) and overall survival (OS). In order to verify the results of the Cleopatra trial in unselected pts, we performed a multicenter, retrospective-prospective, observational study, in HER-2+ MBC pts candidate to receive first line therapy with P plus T plus taxanes. Methods: We analyze the outcome of all HER-2+ MBC pts treated with P+T and taxanes, as first line therapy since the availability of P in Italy (2013), at 13 general and university hospitals. Results: Until June 6th data from 217 HER-2+ MBC pts were recorded. Main pts' characteristics were: median age 54 y (28-80), median ECOG PS 0 (0-2), hormonal receptor positive 152 pts (70%), 60 pts (27.6%) received neo/adjuvant chemotherapy (CT) + T and 75 pts (34.5%) adjuvant endocrine therapy. Most common metastatic sites: bone 121 pts (55.7%), liver 85 pts (39.2%), lung 61 pts (28.1%), soft tissues 133 pts (61.3%); 8 pts had CNS involvement. Seventy-eight pts (35.9%) had bone and/or soft tissues disease only; 108 pts (49.7%) had metastatic disease on presentation. Median number of metastatic sites was 3 (1-8). 144 pts (66.3%) and 72 pts (33.2%) received docetaxel (D) and paclitaxel (P) respectively. Median number of CT cycles was 6 for both drugs (D range 1-13; P range 1-18). Up to now 23 pts are still on CT and 86 on maintenance; ORR in evaluated pts (189) is 80.9% (47 and 106 pts obtained CR and PR respectively), 11 pts experienced PD during CT; 113 pts (58.2%) received endocrine therapy during maintenance.Median PFS is 14.7+ months (0.3+ - 53.2+). Most common adverse events are reported in table 1 Table 1Adverse EventAll grades N (%)Grade 3-4 N (%)Leukopenia39 (18)10 (4.6)Neutropenia42 (19.3)16 (7.3)Anemia50 (23)2 (0.9)Febrile Neutropenia7 (3.2) Diarrhea103 (47.4)10 (4.6)Asthenia127 (58.5)5 (2.3)Peripheral Neuropathy80 (36.8)3 (1.3)Stomatitis67 (30.8)2 (0.9) Nail changes, nausea, alopecia, rash and arthro-myalgia were also reported. Three pts interrupted CT due to symptomatic drop of left ventricular ejection fraction (LVEF); 2 pts interrupted maintenance P due to rash and dyspnea respectively, 16 stopped P and T due to drop in LVEF, 1 due to occurrence of ALL and 1 refused to continue. Conclusions: Our preliminary results highlight the activity and safety of the combination of CT plus P and T in unselected HER-2+ MBC patients. The study is ongoing and updated results will be presented. Citation Format: Garrone O, D'Onofrio L, Blondeaux E, Bertolini I, Giarratano T, Beano A, Saggia C, Cazzaniga M, LaVerde N, Collovà E, Milani A, De Conciliis E, Coltelli L, Airoldi M, Del Mastro L, Cursano MC, Michelotti A, Vandone AM, Guarneri V, Donadio M, Riva F, Nuzzo A, Merlano MC. Moving from the CLEOPATRA study to real life: Preliminary results from the G.O.N.O. SUPER trial [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P5-21-29.

Background: Brain metastases (BM) are a serious relatively common complication of breast cancer (BC). We evaluated prognostic factors for survival after diagnosis of BM from BC in a contemporary cohort of pts. Methods:Pts diagnosed with BM from BC between 1999 and march 2016 and treated at the Istituto Oncologico Veneto of Padua were evaluated. Overall survival (OS) was defined as time from BM diagnosis to death or last follow-up. Pts were classified in 4 categories according to the breast cancer-specific Graded Prognostic Assessment (GPA) index according to validated criteria (Sperduto et al, 2012), based on age, Karnofsky Performance Status (KPS) and BC phenotype. Cox proportional models were used to calculate HR and 95% CI. Results: 199 pts were identified. Median age at BM diagnosis was 56 yrs (range 28-84). Tumor phenotype distribution was as follows: triple negative (TN, 20.1%), hormone receptor (HR)-HER2+ (16.8%), HR+HER2+ (24.0%) and HR+HER2- (39.1%). Median time to BM diagnosis was 48.9 months (range 0-327), with significant differences according to tumor phenotype (median 27.3, 31.8, 46.1 and 55.2 months in TN, HR-HER2+, HR+HER2+, HR+HER2-, respectively, p=0.009). With respect to OS, no significant difference was observed across tumor phenotypes, with TN patients experiencing the worse outcome (median: 4.7, 7.7, 11.0 and 6.2 months in TN, HR-HER2+, HR+HER2+, HR+HER2-, p=0.187). The breast-specific GPA index, which combines tumor phenotype with patient-related features, was significantly associated with OS (Table). The number of local treatment received (radiotherapy, either whole brain or stereotactic, or neurosurgery) and the administration of systemic treatment after BM diagnosis were significantly associated with better OS (Table). Patients in the less favorable GPA category (GPA index Prognostic factorsMedian OS, months (95%CI)HR (95%CI), univariatep, univariateHR (95%CI), corrected for GPAGPA category 3.5-418.8 (15.2-22.5)ref -2.5-38.8 (3.8-13.8)1.40 (0.80-2.43) -1.5-25.5 (3.5-7.5)1.76 (1.00-3.10) -0-1.02.7 (1.2-4.3)2.67 (1.35-5.28)0.019-Number of local tretaments received 03.0 (1.8-7.5)ref ref18.0 (5.8-10.3)0.53 (0.38-0.74) 0.54 (0.38-0.78)221.3 (15.2-27.3)0.36 (0.20-0.65) 0.49 (0.26-0.93)335.5 (33.5-37.6)0.12 (0.04-0.38) Conclusions: Patient-related features, tumor phenotype and multimodal treatments all independently contribute to modulate the prognosis of pts with BM from BC. Citation Format: Griguolo G, Dieci MV, Giarratano T, Giorgi CA, Orvieto E, Ghiotto C, Falci C, Mioranza E, Tasca G, Milite N, Miglietta F, Conte P, Guarneri V. Factors related to the prognosis of breast cancer patients after the development of brain metastases [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P1-12-06.

Background: The integration of Residual Cancer Burden (RCB) and post-treatment Ki67 (Residual Proliferative Cancer Burden [RPCB] index) has been proposed as a stronger predictor of long-term outcome in unselected breast cancer (BC) patients undergoing neoadjuvant chemotherapy (NACT), as compared to RCB. However, no specific analysis in the subgroup of patients with hormone-receptor (HR)-positive/HER2-negative BC is available so far. We investigated the prognostic value of RPCB in an independent cohort of hormone-receptor (HR) positive/HER2 negative BC patients treated with NACT at our Institution. Methods: A cohort of 130 stage II-III, HR+/HER2 negative BC patients who underwent NACT between 2000 and 2014 was included. Archival surgical specimens were evaluated for RCB (Symmans et al. J Clin Oncol 2007). RPCB was calculated by combining RCB and Ki67 as previously described (Sheri et al, Ann Oncol 2015). Patients were categorized in 4 RCB categories (pathological complete response -pCR- and RCB tertiles) and 4 RPCB categories (pCR and RPCB tertiles). Disease-free Survival (DFS) and overall Survival (OS) estimates were determined by Kaplan-Meier analysis and compared using the log-rank test. The c-index was used to compare the performance of the prognostic models. Results: Patients characteristics were: ductal histology 70%, Grade 3 41%, Stage III 54%, PgR negative (≤10%) 35%, median Ki67 at diagnosis 25%. Neoadjuvant chemotherapy included both anthracycline and taxane in 92% of cases. The rate of pCR was 8%. The vast majority of patients received adjuvant endocrine therapy (96%), whereas 30% received further adjuvant chemotherapy. Median follow up was 8.5 years (95% CI 8.0-9.0). RCB was calculated for 105 patients and RPCB was calculated for 85 patients. RPCB was better than RCB in predicting both DFS and OS (5-year DFS and 8-year OS according to RPCB and RCB are reported in the Table). The c-index for DFS prediction was numerically higher for RPCB vs RCB (0.4042316 vs 0.3396437, p=0.08). Similar results were observed for OS prediction: c-index 0.3099490 (RPCB) vs 0.2372449 (RCB), p=0.08. Conclusions: This is the first study evaluating RPCB specifically in HR+/HER2- BC patients treated with NACT. In this independent cohort, after a median follow up of 8.5 years, RPCB was a strong predictor of DFS and OS. The better performance of RPCB vs RCB was in part due to the ability of RPCB to discriminate a subgroup of patients with a particularly worse prognosis after NACT, who may be candidate for clinical trials evaluating novel adjuvant treatments. Five-year DFS and eight-year OS according to RPCB and RCB5-year DFSp-value8-year OSp-valueRPCBpCR100%0.041100% Citation Format: Federica Miglietta, Vassilena Tsvetkova, Maria Vittoria Dieci, Gaia Griguolo, Grazia Vernaci, Alice Menichetti, Cristina Falci, Giovanni Faggioni, Tommaso Giarratano, Simona Frezzini, Eleonora Mioranza, Marcello Lo Mele, PierFranco Conte, Valentina Guarneri. Validation of residual proliferative cancer burden (RPCB) as a predictor of long-term outcome following neoadjuvant chemotherapy in hormone-receptor positive/HER2 negative breast cancer patients [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P5-06-12.

Chemotherapy-induced alopecia (CIA) affects the majority of patients receiving chemotherapy (CT) for early breast cancer. It is a highly distressing side effect of CT, with psychological and social impact. Primary aim of the present analysis was to assess the efficacy of scalp cooling with DigniCap® in preventing CIA. Success rate was defined as patients' self-reported hair loss

Background The ROXANE Italian prospective study evaluated the impact of the 21-gene Recurrence Score (RS) results on adjuvant treatment decision for patients with early breast cancer. Materials and Methods Nine centers participated. Physicians used the RS test whenever unsure about adjuvant treatment recommendation for patients with estrogen receptor-positive/human epidermal growth receptor 2-negative, T1–T3, N0–N1 early breast cancer. Pre-RS and post-RS treatment recommendations were collected. Results A total of 251 patients were included. N0 patients (61%) showed higher grade (p < .001) and higher Ki67 (p = .001) and were more frequently progesterone receptor negative (p = .012) as compared with N1 patients. RS results were as follows: Conclusion Physicians predominantly used the 21-gene assay in N0 patients with a more aggressive biology or in N1 patients showing more indolent biology. In this selected patient population, the use of RS testing led to a 30% rate of change in treatment decision. In the N1 patient subgroup, the use of RS testing contributed to reduce CT use by more than half. Implications for Practice This study shows that, even in a context in which physicians recommend a high proportion of patients to endocrine treatment alone before knowing the results of the Recurrence Score (RS) assay, the use of the RS test, whenever uncertainty regarding adjuvant treatment recommendation is present, significantly contributes in further reducing the use of chemotherapy, especially for N1 patients.

Background Tumor-infiltrating lymphocytes (TILs) evaluated in primary breast cancer (BC) convey prognostic information. Limited data in the metastatic setting are available. Methods Secondary lesions from 94 BC patients, 43 triple-negative (TN) and 51 HER2-positive, were evaluated for TILs and expression of CD8, FOXP3, and PD-L1 by immunohistochemistry. Results TILs levels on metastasis were generally low (median 5%) and did not differ between TN and HER2+ tumors. Younger patients showed significantly lower TILs (p = 0.002). In HER2+ patients, TILs were higher in lung metastases as compared to other sites (p = 0.038). TILs composition was different across metastatic sites: skin metastases presented higher FOXP3 (p = 0.002) and lower CD8/FOXP3 ratio (p = 0.032). Patients treated for metastatic BC prior to biopsy had lower CD8 (overall: p = 0.005, HER2+: p = 0.011, TN: p = 0.075). In TN patients, median overall survival (OS) was 11.8 and 62.9 months for patients with low and high TILs, respectively (HR 0.29, 95%CI 0.11–0.76, log-rank p = 0.008). CD8/FOXP3 ratio was also prognostic in TN patients (median OS 8.0, 13.2, and 54.0 months in 1st, 2nd and 3th tertile, log-rank p = 0.019). Both TILs and CD8/FOXP3 ratio were independent factors at multivariate analysis. Counterintuitively, in HER2+ BC, low TILs tumors showed better prognosis (median OS 53.7 vs 39.9 months in TILs low and TILs high, not statistically significant). Conclusions Our findings indicate the relevance of TILs as prognostic biomarker for TNBC even in the advanced setting and provide novel hypothesis-generating data on potential sources of immune heterogeneity of metastatic BC. Electronic supplementary material The online version of this article (10.1186/s13058-018-1003-1) contains supplementary material, which is available to authorized users.

Background The value of adding carboplatin (Cb) to neoadjuvant chemotherapy for TNBC is debated. Current evidence supports the association between Cb use and increased pathological complete response (pCR) rate. However, treatment schedules and doses adopted in randomized trials were not always consistent with those used in clinical practice. Methods Clinicopathological data of TNBC (ER & PgR Results 166 patients were included: 61% treated with AT, 39% with AT+Cb (all patients in this group received Cb AUC2 weekly administered concomitantly to the taxane segment). Main characteristics: median age 50 yrs, ductal histology 93%, grade 3 90%, cT > 2cm 86%, cN + 57%, median TILs 10%, median Ki67 60%, BRCA mutated 10%. After propensity score matching, pCR rate was significantly higher for AT+Cb vs AT: 52% vs 31% (OR 2.39 95%CI 1.04-5.50, p = 0.040). In multivariable analysis, treatment with AT+Cb maintained an independent association with pCR: OR 2.51 95%CI 1.03-6.11, P = 0.043. The achievement of pCR was significantly associated with improved disease-free survival (HR 0.16, 95%CI 0.06-0.45). No difference in DFS was observed comparing AT+Cb vs AT: HR 0.99, 95%CI 0.44-2.25. Conclusions We confirmed in a clinical practice setting the association of Cb-containing neoadjuvant chemotherapy with higher pCR rates. Additional data are needed to clarify the impact on long-term survival. These data support the conditional positive recommendation for Cb inclusion in neoadjuvant chemotherapy for TNBC provided by the Italian Association of Medical Oncology Guidelines on Breast Cancer. Funding Has not received any funding. Disclosure M.V. Dieci: Advisory / Consultancy: Eli Lilly; Advisory / Consultancy: Celgene; Advisory / Consultancy: Genomic Health. V. Guarneri: Advisory / Consultancy: Eli Lilly; Advisory / Consultancy: Novartis; Advisory / Consultancy: Roche; Speaker Bureau / Expert testimony: Eli Lilly; Speaker Bureau / Expert testimony: Novartis; Research grant / Funding (institution): Roche. All other authors have declared no conflicts of interest.

Background The Breast DX Italy prospective study evaluated the impact of the 21-gene recurrence score (RS) result on adjuvant treatment decisions for patients with early breast cancer. Materials and Methods Nine centers (two Hub and seven Spoke centers of the Veneto Oncology Network) participated. Consecutive patients with estrogen receptor positive, human epidermal growth receptor negative, T1–T3, N0–N1 early breast cancer were prospectively registered; only those meeting protocol-defined clinicopathological “intermediate risk” criteria were eligible for the RS test. Pre-RS and post-RS physicians’ treatment recommendations and treatment actually received were collected. Results A total of n = 124 N0 and n = 126 N1 patients underwent the RS assay. The majority had Grade 2 tumors (71%); median age was 55 years, median tumor size was 16 mm, and median Ki67 expression was 20%. Patients enrolled at Hub centers presented higher-risk features. The distribution of RS results was 30 (6.8%). The indication before RS was hormonal therapy (HT) alone in 52% of cases. An indication before RS of chemotherapy (CT)+HT was more frequent for patients with N1 versus N0 tumors (57% vs. 39%, p = .0035) and for patients enrolled at Hub versus Spoke centers (54% vs. 36%, p = .007). The overall rate of change in treatment decision was 16% (n = 40), mostly from CT+HT to HT (n = 30). According to nodal status, rate of change in treatment decision was 12% for the N0 cohort and 20% for the N1 cohort. The proportion of patients recommended to CT+HT was significantly reduced from before to after RS (48% to 40%, p Conclusion Despite frequent indication of HT before RS, the use of the RS assay further contributed to sparing CT, especially for patients with N1 tumors and at Hub centers. Implications for Practice This study shows that, although a high proportion of patients were recommended to receive endocrine treatment alone before knowing the recurrence score (RS) assay, the RS test further contributed in sparing chemotherapy for some of these patients, especially in case of the N1 stage or for patients enrolled at referral centers. These data highlight the need for further work in collaboration with health authorities and companies in order to define strategies for the implementation of the use of RS testing in clinical practice in the Italian setting.

Brain metastases are a serious relatively common complication of breast cancer. We evaluated prognostic factors for survival after diagnosis of brain metastases from breast cancer in a contemporary cohort of patients. Patients diagnosed with breast cancer brain metastases at our institution between 1999 and March 2016 were evaluated. Overall survival was defined as time from brain metastasis diagnosis to death or last follow-up. Patients were classified according to the Breast cancer-specific Graded Prognostic Assessment (BS-GPA), based on age, Karnofsky performance score and breast cancer phenotype. 181 patients were identified. Tumor phenotype distribution was as follows: triple negative (TN, 18.8%), hormone receptor (HR)−HER2+ (16.6%), HR+HER2+ (23.2%) and HR+HER2− (30.9%), not available (10.5%). Median overall survival from brain metastasis diagnosis was 7.7 mos (95% CI 5.4–10.0 mos). Although TN patients experienced the worse outcome, no significant difference was observed across tumor phenotypes (median 5.1, 7.7, 11.0 and 8.6 months in TN, HR−HER2+, HR+HER2+, HR+HER2−, p = 0.081). The BS-GPA index was significantly associated with overall survival (median 18.8, 8.8, 6.2 and 3.6 months, respectively, for BS-GPA categories 3.5–4, 2.5–3, 1.5–2 and 0–1, p = 0.014). Increased number of local treatments for brain metastasis (radiotherapy or neurosurgery) or the administration of systemic therapy after brain metastasis diagnosis were also significant predictors of better overall survival (p

e13006Background: Approximately 20% of breast cancers (BC) are HER-2+. Trastuzumab (T) has dramatically changed the outcome, both in early and in advanced settings in HER2+BC. Pertuzumab (P) plus T...

e12038 Background: The Breast-DX Italy prospective study evaluated the impact of the 21-gene RS on adjuvant treatment decisions for early BC patients. Methods: The study was conducted in 9 centers of the Veneto Region (2 hub and 7 spoke). All consecutive patients with ER+/HER2-, T1 to T3, N0 to N1 early BC who met protocol-defined clinicopathological criteria for “intermediate risk” were included. Pre-RS and post-RS physicians’ treatment recommendations and treatment actually received were collected. Results: From November 2014 to August 2016, n=124 N0 and n=126 N1 patients were enrolled (65% at hub and 35% at spoke centers). The majority had PgR+ (86%), G2 (71%) and pT1c (63%) BC. Median age was 55 yrs, median Ki67 was 20% (range 2-70%). The distribution of RS was: 30 (7%). Main factors associated with higher RS were G3 and higher ki67. The addition of chemotherapy (CT) to hormonal therapy (HT) was initially recommended for 48% of the patients (38% of N0 and 57% of N1 patients; 54% and 37% of patients enrolled at hub and spoke centers, respectively). The post-RS recommendation changed from the pre-RS recommendation for 40 patients, mostly from CT+HT to HT (n=30; n=25 with low and n=5 with intermediate RS). Change was more frequent for N1 patients (Table). Of the 72 N1 patients initially recommended to CT+HT, 28% had a post-RS indication to HT alone. The crude number of patients with pre-RS recommendation to CT significantly exceeded the number of patients who finally received it (absolute difference =31; p