Many men who are treated with hormone therapy develop some breast enlargement (referred to as gynecomastia) or breast tenderness or pain (mammalgia.) Gynecomastia may occur in as many as 90% of men given estrogen or Flutamide, 8% orchiectomy,  3- 15% Lupron and 19% Lupron plus Flutamide. The most common drugs that cause gynecomastia are noted here.

Low dose radiation will prevent or at least lower the risk of this developing. In one study reduced the risk from 90% to 17%. The usual dose is 9-10 Gy X1 or 12-15Gy in 3-4 fractions two to three days before starting estrogens.

If the man already has significant breast enlargement, the radiation may help with the pain but is not as effective in decreasing the enlargement.

Effective radiotherapy in palliating mammalgia associated with gynecomastia after DES therapy.

Chou JL,Int J Radiat Oncol Biol Phys. 1988 Sep;15(3):749-51.  Department of Radiotherapy, Baylor College of Medicine, Houston, TX.

Between 1977 and 1986, 11 patients with painful gynecomastia after DES therapy were referred for palliative radiotherapy. The treatment regimens varied from 20 Gy in 5 fractions to 40 Gy in 20 fractions. All 11 patients had satisfactory pain relief on follow-up. All 7 patients who had more than 6 months follow-up had complete relief of mammalgia. The average interval between completion of radiotherapy to complete relief of mammalgia was 3.6 months. This study revealed that radiotherapy is highly effective in palliating mammalgia associated with gynecomastia after DES therapy in prostate cancer patients.

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

Dicker AP.   Lancet Oncol. 2003 Jan;4(1):30-6.  Department of Radiation Oncology, Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA 19107-5097, USA.

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.

Radiotherapeutic prophylaxis of estrogen-induced gynecomastia: a study of late sequela.

Fass D, .Int J Radiat Oncol Biol Phys. 1986 Mar;12(3):407-8.

Radiation therapy is an effective means of preventing the development of hormone-induced gynecomastia in men with cancer of the prostate. The efficacy and morbidity of this type of radiation was studied in a retrospective analysis of 87 patients referred for treatment from 1972 to 1982. Patients receiving DES as treatment for prostate carcinoma were treated with irradiation to the breast tissue. Patients were treated with 4 MV, 60Co superficial X rays. Doses range from 1200 to 1500 cGy in 3 fractions. The majority of patients had satisfactory results in terms of prevention of gynecomastia and mammalgia. There were few acute reactions noted and no evidence of long term sequela.

Pre-estrogen breast irradiation for patients with carcinoma of the prostate: a critical review.

Gagnon JD  J Urol. 1979 Feb;121(2):182-4.

We studied 38 patients with prostatic cancer who received breast irradiation before oral estrogen administration. Our data are combined with those from other institutions to determine the effectiveness of pre-estrogen breast irradiation in minimizing gynecomastia and/or pain. Based on our review the incidence of estrogen-induced breast changes is 70%. Irradiation given before estrogen administration can prevent or minimize these changes in 89.3% of the treated patients. Histologic changes of gynecomastia are reviewed and recommendations for optimum radiation therapy technique are included.

Irradiation of the breast glands as prophylactic treatment of an estrogen-induced gynecomastia in patients with prostate carcinomas


Metzger H, Strahlentherapie. 1980 Feb;156(2):102-4.

One hundred and four patients with histologically demonstrated prostate carcinomas were submitted to a bilateral orchiectomy. Before the beginning of a hormone therapy, both breast glands were irradiated prophylactically. The patients were observed between two and thirty months. The radiotherapy was executed with electrons with an energy of 10 to 12 MeV and by a stationary field which had a size of 10 X 10 cm. A total surface dose of 12,0 Gy was applicated in four single doses of 3,0 Gy each. The symptom-less healing of 45% of the pateints and the rate of only 29% of patients with gynecomastia is considered to be a good result. In view of the success achieved by the hormone therapy, subjective complaints such as hyperesthesia, pains and pruritus are regarded to be less important.

Irradiation for prevention of gynecomastia prior to estrogen therapy in cases of carcinoma of the prostate

Rost A.  Urologe A. 1977 Mar;16(2):83-7.

The most frequent and most unpleasant side-effect of therapy with estrogen hormones in patients with carcinoma of the prostate is the painful gynecomastia. Since 1969, we have been performing the prophylactic irradiation of the mammary glands on 284 patients in order to prevent a hormone-induced gynecomastia. The majority (262 patients) was irradiated with 600 rad surface dose in fractions of 150 rad prior to the hormone therapy. One hundred and two patients, having been treated endocrinologically for 2-75 months, had a follow-up examination. After irradiation, only 19% of the patients did not develop a gynecomastia, and 60% had no mamillary hyperesthesias. Compared to other authors, the therapy was less efficient, the symptoms, however, were discrete. As a consequence, an increase of the radiation dose as well as an alteration of the fractionation must be used.

Does prophylactic breast irradiation prevent antiandrogen-induced gynecomastia? Evaluation of 253 patients in the randomized Scandinavian trial SPCG-7/SFUO-3.

Widmark A, .Urology. 2003 Jan;61(1):145-51.

Department of Oncology, Umea University, Umea, Sweden.

OBJECTIVES: To examine the development of antiandrogen-induced gynecomastia and breast tenderness in the first 253 patients in a randomized Scandinavian trial (SPCG-7/SFUO-3) with a 12-month complete follow-up evaluation performed by both doctors and patients. METHODS: In this study, the treating doctor and patient decided whether prophylactic irradiation (RT) of the breast should be given to prevent antiandrogen-induced gynecomastia. At each visit, the doctor evaluated the occurrence of gynecomastia and breast tenderness. Questions about gynecomastia and breast tenderness were also included in the study quality-of-life questionnaire (Prostate Cancer Symptom Scale). RESULTS: Mammary RT with mostly single fraction (12 to 15 Gy) electrons was given to 174 (69%) of the 253 evaluated patients. At the 1-year follow-up visit, the doctor evaluations indicated some form of gynecomastia in 71% and 28% (P <0.001) of the nonirradiated (no-RT) and irradiated (RT) patients, respectively. The patient evaluations at 1 year showed some form of breast enlargement in 78% and 44% (P <0.001) of the no-RT and RT patients, respectively. The doctors reported some form of breast tenderness at 1 year in 75% and 43% (P <0.001) of the no-RT and RT patients, respectively. The patient evaluations of breast tenderness show an expected significant increase in the RT arm at the 3-month follow-up, which was probably due to skin reactions. At 1 year, significantly more patients who marked "very much" on the Prostate Cancer Symptom Scale were seen in the no-RT group. A weak correlation between the doctors' and patients' detection of breast problems was observed. CONCLUSIONS: The results show that, with high significance, prophylactic RT of the breast decreases the risk of antiandrogen-induced gynecomastia and breast tenderness.