Prevention of gynecomastia and breast pain caused by androgen deprivation therapy in prostate cancer: tamoxifen or radiotherapy?

Purpose: To determine, in a meta-analysis, whether gynecomastia and breast pain rates in men with prostate cancer treated with androgen deprivation therapy (ADT) are reduced if treated with prophylactic radiotherapy (RT) or tamoxifen (TMX).

Methods And Materials: The MEDLINE, EMBASE, CANCERLIT, and Cochrane Library databases, as well as proceedings of annual meetings, were systematically searched to identify randomized, controlled studies comparing RT or TMX with observation for men with prostate cancer using ADT.

Results: Six RCTs (three RT trials and three TMX trials, N = 777 patients total) were identified that met the study criteria. Pooled results from these RCTs comparing RT vs. observation showed a significant reduction in the incidence of gynecomastia and breast pain rates in patients treated with RT (odds ratio [OR] = 0.21, 95% confidence interval [CI] = 0.12-0.37, p < 0.0001, and OR = 0.34, 95% CI 0.20-0.57, p < 0.0001, respectively). Use of RT resulted in an absolute risk reduction (ARR) of 29.4% and 19.9%, with a number needed to treat (NNT) of 3.4 and 5 to avoid one case of gynecomastia and breast pain, respectively. Pooled results from trials comparing TMX vs. observation showed a statistical benefit for breast pain and gynecomastia in favor of TMX arms (OR = 0.04, 95% CI = 0.02-0.08, p < 0.0001 and OR = 0.07, 95% CI = 0.0-0.14, p < 0.00001). TMX resulted in an ARR = 64.1% and 47.6%, with an NNT of 1.56 and 2.1 to avoid one case of gynecomastia and breast pain, respectively. Considering adverse effects, TMX was 6 times more adverse effects than RT.

Conclusions: Our data have shown that both TMX and RT prevented gynecomastia and breast pain in patients with prostate cancer receiving ADT for prostate cancer. Although TMX was two times more effective in preventing gynecomastia, RT should represent an effective and safe treatment option, to take into account mainly in patients with cardiovascular risk factors or thrombotic diathesis.