Several hormonal therapies used to treat prostate cancer can cause breast enlargement. This is called gynaecomastia. Casodex® tablets cause gynaecomastia in up to 7 out of 10 men who take them. They can also cause pain or discomfort in the breasts. Treatments, that can help to prevent this, include radiotherapy and tamoxifen.

Radiotherapy

Radiotherapy prevents gynaecomastia in most men (about 7 out of 10) when it is given before hormonal treatment starts. Only a low dose of radiotherapy is needed. It is given to both breasts as an out-patient treatment and takes only a few minutes. It may be given as a single treatment or over 2-3 days. Some men may notice a slight redness of the skin around their breast after radiotherapy but this usually goes away within about 5 weeks.

Tamoxifen

Tamoxifen comes as a tablet and is a hormonal treatment commonly used to treat breast cancer. When used to prevent breast swelling, in men with prostate cancer, it has been shown to work for up to 9 out of 10 men who take it. It’s taken from the time hormonal therapy for prostate cancer is started.

All men and women produce both oestrogen and testosterone. Normally, men’s higher levels of testosterone block (oppose) the effects of oestrogen on their bodies. But hormonal therapy for prostate cancer can upset this balance. So, the effects of oestrogen on breast tissue are greater and can cause breast tissue to grow.

Tamoxifen blocks oestrogen from reaching breast tissue and stops breast enlargement without altering the effectiveness of hormonal treatment for prostate cancer.

If you are worried about developing breast swelling your specialist will be able to tell you more about these treatments.

Reference

• Di Lorenzo, et al (2005) Management of gynaecomastia in patients with prostate cancer: a systematic review. Lancet Oncology 6 972-979.