A recent study conducted in Germany showed a decrease in estradiol levels in men treated for hormone receptor-positive breast cancer, using a gonadotropin-releasing hormone analogue (GnRHa) with tamoxifen or an aromatase inhibitor (AI). The results of this study were published in JAMA Oncology.
The study was the randomized phase 2 MALE clinical trial (ClinicalTrials.gov: NCT01638247) in which 56 patients were allocated across 3 arms for 6 months of treatment with the arms consisting of tamoxifen only, tamoxifen with a GnRHa, or an AI with a GnRHa. The change from baseline to 3 months in 17-β-estradiol levels was the primary endpoint. Multiple secondary endpoints also were evaluated.
Treatment was begun in 52 patients, and 1 patient per arm discontinued therapy early. The median age of patients who started therapy was 61.5 years (range, 37 to 83).
There were 50 evaluable patients for the analysis of the primary endpoint, with 17 receiving tamoxifen alone, 15 receiving tamoxifen with a GnRHa, and 18 receiving a GnRHa with exemestane as the AI. The study investigators reported a median 3-month increase in 17-β-estradiol levels by 67% (or +17.0 ng/L) for patients receiving tamoxifen only, a median 85% decrease (–23.0 ng/L) for patients receiving tamoxifen with a GnRHa, and a median 72% decrease (–18.5 ng/L) for those receiving an AI with a GnRHa (P <.001).
Percent changes in 17-β-estradiol levels at 6-months were +41% (+12.0 ng/L) with tamoxifen alone, –61% (–19.5 ng/L) with tamoxifen and a GnRHa, and –64% (–17.0 ng/L) with an AI plus a GnRHa (P <.001). The study investigators reported that there were also improvements in sexual function and quality of life for the study arms that included a GnRHa, but that there were no changes in these parameters for patients receiving tamoxifen alone.
“The addition of GnRHa to [an] AI or tamoxifen leads to a more profound suppression of estradiol, which is known to increase survival in premenopausal women,” the study investigators concluded in their report.
Disclosures: Several study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.
Reinisch M, Seiler S, Hauzenberger T, et al. Efficacy of endocrine therapy for the treatment of breast cancer in men: results from the MALE phase 2 randomized clinical trial. JAMA Oncol. 2021;7(4):565-572. doi:10.1001/jamaoncol.2020.7442