Treatment of male breast cancer: meta-analysis of real-world evidence

Abstract

Background: Breast cancer is rare in men and managed by extrapolating from breast cancer in women. The clinicopathological features of male breast cancer, however, differ from those of female breast cancer. Because clinical trials are rare, the synthesis of real-world data is one method of integrating sufficient evidence on the optimal treatment for this patient population. Methods: PubMed, Embase, and Cochrane Library databases were searched. Clinical studies were included if they evaluated the treatments of interest in male breast cancer; these evaluations included breast-conserving surgery (BCS) versus mastectomy, postmastectomy radiation therapy versus no radiation, the accuracy of sentinel lymph node biopsy (SLNB), and a comparison of various endocrine therapies. Results: Forty studies were retrieved. The pooled estimate of overall survival (OS) revealed no difference between BCS and mastectomy groups. Postmastectomy radiation to the chest wall significantly increased OS relative to no postmastectomy radiation (hazard ratio (HR) 0.67, 95 per cent confidence interval 0.54 to 0.84). The pooled estimates of identification and false-negative rates of SLNB were 97.4 and 7.4 per cent respectively. Tamoxifen treatment was associated with significantly increased OS compared with no tamoxifen intake (HR 0.62, 0.41 to 0.95). Conclusion: Identification and false-negative rates for SLNB were comparable to those in female breast cancer. Breast-conserving surgery can be effective and safe; postmastectomy radiation to the chest wall and 5-year tamoxifen treatment improves survival.