Familial Cancer Service, Westmead Hospital; Centre for Cancer Research, Westmead Millennium Institute, University of Sydney, Sydney, Australia
Male breast cancer (MBC) accounts for less than 1% of all breast cancers. The risk increases with age and the mean age at diagnosis is 60-70 years. Family history of breast cancer is an important risk factor for MBC but heritable mutations in the two major breast cancer susceptibility genes BRCA1 and (more often) BRCA2 account for only 10% or less of all MBC. PALB2 mutations have also been associated with an increased risk of MBC.
The possibility of a genetic susceptibility to breast/ovarian cancer should be considered at the time of MBC diagnosis. This is when the family history should be taken. Indications for testing the genes BRCA1 and BRCA2 have broadened but now include more rigorous assessment of the chance of finding a mutation based on a particular family history and/or breast cancer pathology. For BRCA2 related MBC, pathological grade is higher than for sporadic MBC, but decreases with age. BRCA1/2 MBC are higher stage, and more likely ER/PR positive compared to female BRCA related cancers. For a man with breast cancer at age 75 with a known large family and no other cases of breast cancer, the chance of a BRCA mutation is 0.3%. The chance of finding a mutation increases considerably with family history of early onset breast cancer and/or epithelial ovarian cancer and with Jewish ancestry. Thus testing is offered based on age, family size, ethnicity and family history but is not undertaken in all males with breast cancer. Testing usually starts with an affected family member. It would not impact immediate management as men with a BRCA1/2 mutation do not have a high enough contralateral risk to advise bilateral mastectomy.