Larissa A. Korde

1073 Background: There is significant heterogeneity in the natural history of MBC. Several recent randomized CT have yielded statistically significant advantages for the experimental arm, but neither led to regulatory approval nor practice change. Formal guidance for industry on CT endpoints provided by the US FDA in 2007 was not disease-specific. Patient-focused drug development is mandated by Prescription Drug User Fee Act V. Our WG sought to create specific consensus on endpoints for MBC CT focusing on subtype and line of therapy, with sensitivity to various stakeholders. Methods: A WG composed of medical oncologists, statisticians, advocates, FDA and NCI liaisons performed a systematic literature review of MBC natural history, CT endpoints by subtype (HR+/HER2-, HR+/HER+, HR-/HER2-, HR-/HER2+), and line of therapy (n = 146 papers). External expertise was obtained on industry perspectives, big data and real world evidence (RWE), and patient reported outcomes (PROs). WG members voted anonymously on statements and positions generated from deliberation. Results: The WG reached consensus on definitions relevant to contemporary CT endpoints. WG recommendations on the appropriate choice of OS or PFS are sensitive to expected post progression survival (PPS), and proportional and absolute gains. Currently, for HR-/HER2- MBC, OS is preferred as the optimal primary endpoint regardless of line of therapy; PFS is preferred in settings where expected PPS is longer. Toxicity can outweigh modest gains in PFS; scant data exist to gauge how patients value PFS gain vs toxicity. Where new agents may prolong PFS without impacting OS, exploring/validating graphic approaches that capture grade and timing of toxicity and PROs is warranted. An overview of WG Consensus Statements will be presented in detail. Conclusions: CT design for MBC should be sensitive to natural history (PPS), availability of other effective agents, PROs and toxicity burden. As unique subtypes (e.g. AR+) and novel therapies (e.g. immunotherapy) emerge, reassessment of relevant benchmarks is indicated. Rigorous big data approaches providing insights from RWE may inform CT endpoints in the future.

Much can be learned from small single‐institution studies in male breast cancer; however, individual studies represent only small steps toward our understanding of this rare disease. International collaborative efforts are necessary to make the great strides needed to discern the unique biology, genetics, and optimal treatment for male breast cancer and to best serve patients with this disease.

This analysis addresses risk of breast cancer among women in BRCA-positive families who test negative for the family mutation. We compared the number of prospectively diagnosed breast cancers in 395 mutation-negative women from 28 BRCA1/2-positive families to an age-, race-, and calendar time-specific expected number of breast cancers derived from the SEER 9 Cancer Registry. Study participants contributed a total of 7008.1 person-years of follow-up. The mean age at study entry was 31.3 years; mean follow-up was 17.7 years. Ten women developed breast cancer yielding an observed-to-expected ratio of 0.82 (95% CI 0.39–1.51). Adjustment for possible reduction in breast cancer risk due to oophorectomy by two different methods resulted in O/E ratios in the range of 0.80–0.99. Stratification by degree of relatedness to the nearest mutation carrier did not substantially alter these results, however, women with at least one-first degree relative with breast cancer appeared to have a slightly increased, though not statistically significant, risk of breast cancer (O/E ratio = 1.33, 95% CI 0.41–2.91). Our data suggest that breast cancer risk among mutation-negative women from BRCA1/2 mutation-positive families is similar to that observed in the general population, with a possible slight increase in risk among mutation-negative women with a family history of breast cancer in a first degree relative. Although this is the largest prospective cohort yet assembled to address this important question, the number of breast cancer events is still relatively small.

Male breast cancer is a rare disease, accounting for less than 1% of all breast cancer diagnoses worldwide. Most data on male breast cancer comes from small single-institution studies, and because of the paucity of data, the optimal treatment for male breast cancer is not known. This article summarizes a multidisciplinary international meeting on male breast cancer, sponsored by the National Institutes of Health Office of Rare Diseases and the National Cancer Institute Divisions of Cancer Epidemiology and Genetics and Cancer Treatment and Diagnosis. The meeting included representatives from the fields of epidemiology, genetics, pathology and molecular biology, health services research, and clinical oncology and the advocacy community, with a comprehensive review of the data. Presentations focused on highlighting differences and similarities between breast cancer in males and females. To enhance our understanding of male breast cancer, international consortia are necessary. Therefore, the Breast International Group and North American Breast Cancer Group have joined efforts to develop an International Male Breast Cancer Program and to pool epidemiologic data, clinical information, and tumor specimens. This international collaboration will also facilitate the future planning of clinical trials that can address essential questions in the treatment of male breast cancer.

Neoadjuvant chemotherapy has been shown to be equivalent to post-operative treatment for breast cancer, and allows for assessment of chemotherapy response. In a pilot trial of docetaxel (T) and capecitabine (X) neoadjuvant chemotherapy for Stage II/III BC, we assessed correlation between baseline gene expression and tumor response to treatment, and examined changes in gene expression associated with treatment. Patients received four cycles of TX. Tumor tissue obtained from Mammotome™ core biopsies pretreatment (BL) and post-cycle 1 (C1) of TX was flash frozen and stored at −70°C until processing. Gene expression analysis utilized Affymetrix HG-U133 Plus 2.0 GeneChip arrays. Statistical analysis was performed using BRB Array Tools after RMA normalization. Gene ontology (GO) pathway analysis used random variance t tests with a significance level of P < 0.005. For gene categories identified by GO pathway analysis as significant, expression levels of individual genes within those pathways were compared between classes using univariate t tests; those genes with significance level of P < 0.05 were reported. PAM50 analyses were performed on tumor samples to investigate biologic subtype and risk of relapse (ROR). Using GO pathway analysis, 39 gene categories discriminated between responders and non-responders, most notably genes involved in microtubule assembly and regulation. When comparing pre- and post-chemotherapy specimens, we identified 71 differentially expressed gene categories, including DNA repair and cell proliferation regulation. There were 45 GO pathways in which the change in expression after one cycle of chemotherapy was significantly different among responders and non-responders. The majority of tumor samples fell into the basal-like and luminal B categories. ROR scores decreased in response to chemotherapy; this change was more evident in samples from patients classified as responders by clinical criteria. GO pathway analysis identified a number of gene categories pertinent to therapeutic response, and may be an informative method for identifying genes important in response to chemotherapy. Larger studies using the methods described here are necessary to fully evaluate gene expression changes in response to chemotherapy.