Management and outcome of male metastatic breast cancer in the national multicenter observational research program Epidemiological Strategy and Medical Economics (ESME)

Background and Aims: Because of its low prevalence, metastatic breast cancer (MBC) in males is managed based on clinical experience with women. Using a real-life database, we aim to provide a comprehensive analysis of male MBC characteristics, management and outcome. Methods: The Epidemiological Strategy and Medical Economics Data Platform collected data for all men and women > 18 years with MBC in 18 participating French Comprehensive Cancer Centers from January 2008 to November 2016. Demographic, clinical, and pathological characteristics were retrieved, as was treatment modality. Men were matched 1:1 to women with similar characteristics. Results: Of 16,701 evaluable patients, 149 (0.89%) men were identified. These men were older (median age 69 years) and predominantly had hormone receptor HR+/HER2- disease (78.3%). Median overall survival (OS) was 41.8 months [95% confidence interval (CI: 26.9-49.7)] and similar to women. Median progression-free survival (PFS) with first-line therapy was 9.3 months [95% CI (7.4-11.5)]. In the HR+/HER2- subpopulation, endocrine therapy (ET) alone was the frontline treatment for 43% of patients, including antiestrogens (n = 19), aromatase inhibitors (n = 15) with luteinizing hormone-releasing hormone (LHRH) analogs (n = 3), and various sequential treatments. Median PFS achieved by frontline ET alone was similar in men [9.8 months, 95% CI (6.9-17.4)] and in women [13 months, 95% CI (8.4-30.9)] (p = 0.80). PFS was similar for HR+/HER2- men receiving upfront ET or chemotherapy: 9.8 months [95% CI (6.9-17.4)] versus 9.5 months [95% CI (7.4-11.7)] (p = 0.22), respectively. Conclusion: MBC management in men and women leads to similar outcomes, especially in HR+/HER2- patients for whom ET should also be a cornerstone. Unsolved questions remain and successfully recruiting trials for men are still lacking.