Locoregional Management of Clinically Node-Negative Male Breast Cancer: An Analysis of a Clinical Oncology Database.

Abstract

Male breast cancer (BC) is a rare malignancy with a lifetime risk of one in one thousand. Even for early-stage disease, mastectomy (ME) has traditionally been the treatment of choice. Breast-conserving surgery (BCS) as part of a breast-conserving therapy (BCT) paradigm is an important consideration with a potential of being equally oncologically effective yet less morbid with better functional and more desirable cosmetic outcomes. Since treatment strategies for male BC are extrapolated from the high-level data on female BC, adjuvant radiotherapy (aRT) is a mandatory component of BCT. We sought to investigate the patterns of utilization of ME, BCS, and aRT in a large retrospective cohort of patients. The National Cancer Database (NCDB) was queried for men who received definitive treatment for clinically staged T1-3N0 BC from 2004 to 2013. Patients were excluded if pathologic, receptor subtype or treatment (chemotherapy, endocrine therapy, radiotherapy) data were missing. Chi-square tests and independent two sample t-tests were used to examine the factors associated with receiving ME vs. BCS, and aRT vs. not. We identified 4280 men meeting inclusion criteria with 73% undergoing ME and 27% undergoing BCS. Among all patients, 84% were hormone receptor-positive and Her2-negative, 5% were triple positive, 3% were triple negative, and 8% had borderline or not fully known receptor status. Among all patients, 77 % were white, 10% - black, and 13% represented other races. The following factors were associated with patients undergoing ME compared to BCS: treatment at an academic rather than non-research center, older age, higher CDCI, higher tumor grade and higher clinical T stage (all P < .001). Among the cohort, 76% of the BCS and 17% of the ME groups received aRT. Undergoing BCS, younger age, lower CDCI, presence of positive lymph nodes, and unfavorable receptor subtype were positively associated with receipt of aRT (all P < .001). In this large observational cohort of males with early breast cancer, most were hormone receptor-positive and Her2-negative, and three quarters received ME. A total of 24% of patients who underwent BCS did not receive adjuvant radiotherapy. Further insight into the rationale behind the utilization of different forms of treatment and their impact on outcomes is required.