The safety and tolerability of low-dose irradiation for the management of gynaecomastia caused by antiandrogen monotherapy.

Gynaecomastia--a benign and often painful enlargement of the male breast--is a common side-effect of some therapies for prostate cancer, including non-steroidal antiandrogen monotherapy. Although gynaecomastia and breast pain are not harmful to the overall health of the patient, they can be serious enough to influence treatment decisions in the management of prostate cancer. Prophylactic low-dose irradiation can be effective in reducing the incidence and severity of both gynaecomastia and breast pain. In addition, irradiation may be effective in treating breast pain due to the development of gynaecomastia. Low-dose electron irradiation confers advantageous tissue dosing, is well tolerated, and has manageable side-effects, the most common of which is reversible skin erythema. Information on long-term safety after irradiation for gynaecomastia is limited at present, but trials are underway. Irradiation is likely to be an effective management option with an acceptable low risk of long-term complications for gynaecomastia associated with hormone therapy for prostate cancer.