Male breast cancer (MBC) is a rare disease compared with female breast cancer (FBC), but its incidence is increasing. Because of its rarity, MBC is often compared with FBC and our current understanding regarding MBC biology, natural history and treatment strategies has been largely extrapolated from the female counterpart.
Based on age-frequency distribution, age-specific incidence rate patterns and prognostic factors profiles, MBC is considered similar to late-onset post-menopausal estrogen/progesterone receptors (ER/PR)-positive FBC. This suggests that common BC risk factors may affect both genders. Indeed, similar to BC in women, MBC is likely to be caused by the concurrent effects of different risk factors, including hormonal, environmental and genetic risk factors. However, clinical and pathological characteristics of MBC do not exactly overlap FBC. Compared with women, BC occurs in men later in life, is mostly represented by invasive ductal carcinoma with higher stage, lower grade and ER/PR expression.
Although rare, MBC remains a substantial cause for morbidity and mortality in men, probably because of its occurrence in advanced age and delayed diagnosis. MBC treatment generally follows the same indications as post-menopausal FBC. BC mortality and survival rates have improved significantly over time for both male and female BC, but the improvement for male is smaller if compared to female patients, thus suggesting a delay or non-appropriate utilization of adjuvant therapy.
Overall, much still needs to be learned about MBC and, because of its rarity, the main effort is to develop national and international consortia for moving forward in our understanding of MBC.