What causes breast cancer in men?

Men have a small amount of breast tissue, so cancer can begin in the ducts behind the nipple. The cell changes may happen without a clear single cause. An inherited BRCA gene mutation can increase susceptibility, and a family history of breast or ovarian cancer may be a useful clue to inherited risk.

Other factors that can influence risk include getting older, conditions that alter the balance of male and female hormones, previous radiation to the chest, and some testicular or liver conditions. Having a risk factor does not mean cancer will develop, and many men diagnosed with breast cancer have no obvious risk factor.

Arrange a medical assessment for a firm lump, nipple inversion, nipple discharge, a sore that does not heal, or a change in the skin or nipple. The clinician may examine the chest and armpit and arrange imaging or a biopsy. Tell the team about relatives with breast, ovarian, pancreatic, or prostate cancer and any prior chest radiation.

If cancer is confirmed, testing the tumour helps guide treatment. Genetic counselling may be offered when the personal or family history suggests an inherited mutation. Do not wait for pain; breast cancer can begin with a painless change.

Book an appointment promptly for a new breast or underarm lump, nipple discharge, bleeding, persistent crusting, or a noticeable change on one side. Seek urgent care for heavy bleeding, severe infection signs, or sudden breathing difficulty, while remembering that urgency is based on the symptom and its severity, not on assuming its cause.

Ask whether imaging or biopsy is needed, whether genetic counselling is appropriate, which relatives’ cancer histories matter, and whether hormone-receptor or other tumour testing will affect treatment choices.