Aromatase inhibitors and contralateral breast cancer in BRCA mutation carriers.

BACKGROUND: Deleterious BRCA mutations confer a significant lifetime risk of breast cancer (BC) as well as contralateral BC (CBC) in patients who do not undergo prophylactic mastectomy. Prior reports have suggested that tamoxifen reduces the risk of CBC in BRCA mutation carriers. Whether aromatase inhibitors (AI) have the same effect is unknown. METHODS: This is a retrospective review of patients diagnosed with non-metastatic ER+ BC between 2004 and 2014 with known BRCA mutation status. Patients were followed from primary diagnosis until CBC diagnosis or death. Median follow-up was 11.5 years. Risk of CBC was evaluated as time to event. RESULTS: 935 subjects were included in this analysis, with 53 BRCA1 mutation carriers, and 94 BRCA2 mutation carriers. Median age at diagnosis was 42.7 years. Seventy-two percent (676) received tamoxifen and 43% (405) received AI. A total of 66 CBCs occurred, of which 10% (15/147) occurred in BRCA mutation carriers vs 6.5% (51/788) in BRCA wild type. Multivariate analyses indicated that BRCA status and AI use were significantly associated with CBC risk. AI use resulted in a significant reduction in risk of CBC (HR 0.44, p = 0.004) regardless of the BRCA mutation status. Tamoxifen use was not associated with reduced risk of CBC. CONCLUSIONS: This is the first report showing that AIs reduce the risk of CBC in BRCA mutation carriers. The potential role of AIs as chemoprevention should be validated in larger independent cohorts.

Proteogenomic Markers of Chemotherapy Resistance and Response in Triple-Negative Breast Cancer.

Microscaled proteogenomics was deployed to probe the molecular basis for differential response to neoadjuvant carboplatin and docetaxel combination chemotherapy for triple-negative breast cancer (TNBC). Proteomic analyses of pretreatment patient biopsies uniquely revealed metabolic pathways, including oxidative phosphorylation, adipogenesis, and fatty acid metabolism, that were associated with resistance. Both proteomics and transcriptomics revealed that sensitivity was marked by elevation of DNA repair, E2F targets, G2-M checkpoint, interferon-gamma signaling, and immune-checkpoint components. Proteogenomic analyses of somatic copy-number aberrations identified a resistance-associated 19q13.31-33 deletion where LIG1, POLD1, and XRCC1 are located. In orthogonal datasets, LIG1 (DNA ligase I) gene deletion and/or low mRNA expression levels were associated with lack of pathologic complete response, higher chromosomal instability index (CIN), and poor prognosis in TNBC, as well as carboplatin-selective resistance in TNBC preclinical models. Hemizygous loss of LIG1 was also associated with higher CIN and poor prognosis in other cancer types, demonstrating broader clinical implications. SIGNIFICANCE: Proteogenomic analysis of triple-negative breast tumors revealed a complex landscape of chemotherapy response associations, including a 19q13.31-33 somatic deletion encoding genes serving lagging-strand DNA synthesis (LIG1, POLD1, and XRCC1), that correlate with lack of pathologic response, carboplatin-selective resistance, and, in pan-cancer studies, poor prognosis and CIN. This article is highlighted in the In This Issue feature, p. 2483.

Phase 2 Trial of Capecitabine, Gemcitabine, and Bevacizumab in Sarcomatoid Renal-Cell Carcinoma.

BACKGROUND: Patients with sarcomatoid renal-cell carcinomas (sRCC) have poor outcomes and limited treatment options. Preclinical and clinical data suggest susceptibility to cytotoxic agents and vascular endothelial growth factor-targeted therapies. We designed a phase 2 trial to evaluate the efficacy and safety of capecitabine, gemcitabine, and bevacizumab in sRCC. PATIENTS AND METHODS: Patients with metastatic or unresectable sRCC were eligible for inclusion. Patients received oral capecitabine 800 mg/m2 twice daily on days 1 to 21 of a 28-day cycle, intravenous gemcitabine 900 mg/m2 on days 1 and 15, and intravenous bevacizumab 10 mg/kg on days 1 and 15. Primary end points were progression-free survival and time to treatment failure (TTF). Secondary end points were safety, objective response rate, and overall survival. RESULTS: Thirty-four patients were enrolled onto the trial. One patient was excluded from survival analysis and 4 from response analysis as a result of missing data. Median progression-free survival was 5.5 months (95% confidence interval [CI], 3.4-7.7), median TTF was 4.2 months (95% CI, 2.4-6.0), and median overall survival was 12 months (95% CI, 10.6-13.4). Objective response rate was 20% (5 partial responses, 1 complete response), and disease control rate was 73%. Thirty-one (91%) of the 34 patients discontinued treatment. The most common reason for treatment discontinuation was progressive disease, which occurred in 24 patients (71%). The most common grade 3 toxicity was rash (including hand-foot syndrome) in 24% patients. CONCLUSION: The combination of capecitabine, gemcitabine, and bevacizumab is an option for patients with sRCC; however, response rates are low. Novel therapies are needed to improve outcomes in patients with sRCC.