The use of neoadjuvant therapy increases the rate of breast conservation in men with locally advanced breast cancer

Background: Male breast cancer (MBC) is often diagnosed at a later stage and with a more unfavorable tumor-to-breast ratio compared to women, prompting lower rates of breast conservation (BCT). We sought to assess the practice patterns of neoadjuvant therapy (NT) in MBC patients and the impact on BCT.

Methods: Men with nonmetastatic, invasive breast cancer were identified from the National Cancer Database. Patients were categorized as having small (cT1/2) or locally advanced (cT3/4) tumors and by whether they received NT (which included endocrine or chemotherapy). Univariate and multivariable analyses were performed to assess patterns of NT use and rates BCT.

Results: Of 15,151 male patients, 4.8% received NT and 21.6% underwent BCT. NT was more common among males with cT3/4 tumors than those with cT1/2 tumors (8.2 vs. 2.1%, P < .001). Overall, unadjusted rates of BCT were higher for patients receiving NT in the cT3/4 subgroup (19.0 vs. 12.5%, P < .001), a difference which persisted on multivariable analysis. For all patients analyzed, overall survival (OS) did not differ between males who underwent NT and those who did not (110 vs. 122 months, P = .67), but NT was associated with poorer OS in both univariate and multivariate analyses for patients with cT3/4 tumors (both P < .01).

Conclusions: Men with invasive breast cancer have an expected low rate of BCT, but NT appears to reduce the use of mastectomy in patients with locally advanced cancers. More work is needed to understand the impacts of BCT on locoregional recurrence and disease-free and overall survival for MBC.