Bicalutamide-induced gynaecomastia: do we have the answer?

A randomized trial comparing tamoxifen therapy vs. tamoxifen prophylaxis in bicalutamide-induced gynecomastia

BACKGROUND

Tamoxifen (TAM) has been shown to be active against the bicalutamide-induced breast events (BEs) gynecomastia, and breast pain in patients with prostate cancer (PC). Optimal doses and schedules are not yet established. Debate still exists about whether prophylaxis with TAM is more effective than treatment of BEs when diagnosed. The results of a randomized study comparing TAM prophylaxis vs. TAM therapy are presented.

METHODS

One hundred seventy-six patients with prostate cancer (PC) who were candidates for bicalutamide monotherapy were randomized to receive TAM 20 mg daily orally within 1 month from the onset of BEs (arm A) vs. TAM 10 mg daily starting simultaneously with bicalutamide (arm B). TAM was administered for up to 1 year. BEs were evaluated by a self-administered visual analogue scale. Neither ultrasonography nor calipers were used to measure the degree of gynecomastia.

RESULTS

In arm A, BEs showed a prevalence, increasing with time up to 78.3%. After therapy with TAM they persisted in 27.7% of cases. Two patients (3%) interrupted TAM therapy because of dizziness, and 3 patients (4%) interrupted bicalutamide therapy because of painful gynecomastia. In arm B, the prevalence of BEs was 35% after 12 months of therapy. The difference in BEs between the 2 arms was statistically significant (P < .0001). The differences in prevalence of gynecomastia and breast pain between the 2 arms both favored TAM prophylaxis (P < .0001 and P < .001, respectively). Up to 35% of patients had BEs of low intensity, never requiring bicalutamide withdrawal. Two patients (3%) interrupted the treatment because of gastrointestinal intolerance. No difference emerged between the 2 arms in terms of prostate-specific antigen (PSA) response, plasma testosterone levels, and tumor progression.

CONCLUSION

Bicalutamide-induced BEs can be prevented to a significant degree by prophylaxis with TAM 10 mg/day or effectively treated with TAM therapy 20 mg/day. Persisting BEs are of higher intensity after therapy than after prophylaxis.

Tamoxifen for the management of breast events induced by non-steroidal antiandrogens in patients with prostate cancer: a systematic review

BACKGROUND

Tamoxifen has emerged as a potential management option for gynecomastia and breast pain due to non-steroidal antiandrogens, and it is considered an alternative to surgery or radiotherapy. The objective of this systematic review was to assess the benefits and harms of tamoxifen, in comparison to other treatment options, for either the prophylaxis or treatment of breast events induced by non-steroidal antiandrogens in prostate cancer patients.

METHODS

We searched CENTRAL, MEDLINE, EMBASE, reference lists, the abstracts of three major conferences and three trial registers to identify ongoing randomized controlled trials (RCTs). Two authors independently screened the articles identified, assessed the trial quality and extracted data. The protocol was prospectively registered (CRD42011001320; http://www.crd.york.ac.uk/PROSPERO).

RESULTS

Four studies were identified. Tamoxifen significantly reduced the risk of suffering from gynecomastia (risk ratio 9RR0 0.10, 95% CI 0.05 to 0.22) or breast pain (RR 0.06, 95% CI 0.02 to 0.17) at six months compared to untreated controls. Tamoxifen also showed a significant benefit for the prevention of gynecomastia (RR 0.22, 95% CI 0.08 to 0.58) and breast pain (RR 0.25, 95% CI 0.10 to 0.64) when compared to anastrozole after a median of 12 months. One study showed a significant benefit of tamoxifen for the prevention of gynecomastia (RR 0.24, 95% CI 0.09 to 0.65) and breast pain (RR 0.20, 95% CI 0.06 to 0.65) when compared with radiotherapy at six months. Radiotherapy increased the risk of suffering from nipple erythema and skin irritation, but there were no significant differences for any other adverse events (all P>0.05).

CONCLUSIONS

The currently available evidence suggests good efficacy of tamoxifen for the prevention and treatment of breast events induced by non-steroidal antiandrogens. The impact of tamoxifen therapy on long-term adverse events, disease progression and survival remains unclear. Further large, well-designed RCTs, including long-term follow-ups, are warranted. Also, the optimal dose needs to be clarified.

Optimal prophylactic and definitive therapy for bicalutamide-induced gynecomastia: results of a meta-analysis

OBJECTIVE

Bicalutamide is approved as an adjuvant to primary treatments (radical prostatectomy or radiotherapy) or as monotherapy in men with locally advanced, nonmetastatic prostate cancer (pca). However, this treatment induces gynecomastia in most patients, which often results in treatment discontinuation. Optimal therapy for these breast events is not known so far. We undertook a meta-analysis to assess the efficacy of various treatment options for bicalutamide-induced gynecomastia.

METHODS

The medline, cancerlit, and Cochrane library databases were searched and the Google search engine was used to identify prospective and retrospective controlled studies published in English from January 2000 to December 2010 comparing prophylactic or curative treatment options with a control group (no treatment) for pca patients who developed bicalutamide-induced gynecomastia. Radiotherapy-induced cardiotoxicity was also evaluated.

RESULTS

The search identified nine controlled trials with a total patient population of 1573. Pooled results from prophylactic trials showed a significant reduction of gynecomastia in pca patients treated with prophylactic tamoxifen 20 mg daily (odds ratio: 0.06; 95% confidence interval: 0.05 to 0.09; p = 0.09), and pooled results from treatment trials showed a significant response of gynecomastia to definitive radiotherapy (odds ratio: 0.06; 95% confidence interval: 0.01 to 0.24; p < 0.0001). Aromatase inhibitors and weekly tamoxifen were not found to be effective as prophylactic and curative options. For the radiotherapy, skin-to-heart distance was found to be an important risk factor for cardiotoxicity (p = 0.006). A funnel plot of the meta-analysis showed significant heterogeneity (Egger test p < 0.00001) because of low sample size.

CONCLUSIONS

Our meta-analysis suggests using prophylactic tamoxifen 20 mg daily as the first-line preventive measure and radiotherapy as the first-line treatment option for bicalutamide-induced gynecomastia. Aromatase inhibitors and weekly tamoxifen are not recommended.