Male breast cancer

Male breast cancer
The pink and blue ribbon is used to signal awareness of male breast cancer.
Specialty	Oncology

Male breast cancer (MBC) is a cancer in males that originates in their breasts. Males account for less than 1% of new breast cancers with about 20,000 new cases being diagnosed worldwide every year.^[1][2] Its incidence rates in males vs. females are, respectively, 0.4 and 66.7 per 100,000 person-years (person-years is the number of new cases divided by the product of the relevant population's size multiplied by the average number of years of observation, i.e. new cases ÷ [population × years]). The worldwide incidences of male as well as female breast cancers have been increasing over the last few decades.^[3] Currently, one of every 800 men are estimated to develop this cancer during their lifetimes.^[1]

Because it has a far lower incidence in males and because large-scale breast cancer studies have routinely excluded males, current knowledge of male breast cancer is far less than female breast cancer and often rests on small, retrospective, single-center studies.^[4] Consequently, the majority of strategies for evaluating and treating MBC have been adopted from those used for female breast cancer.^[5] However, MBC appears to have some features that warrant clinical approaches differing from those for female breast cancer.^[4] Features of male breast cancers that differ from those in females include variations in their presentations, associations with other diseases, associations with non-medical predisposing conditions, expressions of key breast cancer-related hormones, causes (including frequency and forms of genetic alterations), tumor types, and treatments.^[4]