OBJECTIVES: To forecast the incident cases of male breast cancer (MBC) in eight high-income European countries: France, Germany, Ireland, Italy, Netherlands, Spain, Sweden, and the United Kingdom over a 10-year period, and to report the expected stage at diagnosis and molecular subtype in these countries.

METHODS: The incidence of MBC was ascertained from national cancer registries, or an average of regional registries, reporting newly diagnosed cases of breast cancer (ICD-10 C50) in males. Stage at diagnosis and molecular subtype data was collated from peer reviewed publications reporting data in European countries.

RESULTS: The crude incidence of MBC ranges from 1.2 per 100,000 to 1.9 per 100,000 in the United Kingdom and Italy respectively. Over the next 10 years we expect demographic changes to result in an increase of incident cases of MBC of 1.2% per year in Germany to 2.9% per year in Ireland. The average stage of diagnosis in MBC in these eight European countries is 36%, 41%, 18%, and 6% for stages I through IV respectively. Approximately 93% and 81% of MBC tumours express the estrogen receptor (ER) and progesterone receptor (PR) respectively, and 7% overexpress HER2+. The predominant molecular subtype (St Gallen classification) of MBC is luminal A (57%; 34-75%) followed by luminal B (39%; 21-51%), basal/triple negative (4%; 3-4%), and ER-/PR-/HER2+ (0.3%; 0-1%).

CONCLUSIONS: MBC stage at diagnosis and molecular subtype differ greatly from female breast cancer, and demographic changes will drive an increase in cases over the next decade. Currently there are no guidelines for the treatment of MBC. An American Society of Clinical Oncology (ASCO) guideline summary for MBC had “Evidence quality: low” for all recommendations. Further real-world evidence-based outcomes studies are needed to definitively ascertain prognostic risk by molecular subtype, stage and treatment to inform treatment guidelines for MBC patients.