Radiotherapy and Male Breast Cancer: A Population-based Registry Analysis

The local-regional management of female breast cancer has been extensively investigated worldwide. The optimal approach for males diagnosed with breast cancer is less clear. We have analyzed the treatment of male breast cancer using a population-based national registry to determine the impact of surgery and radiation therapy on survival.

The Surveillance Epidemiology and End Results (SEER) database was queried to identify males with invasive ductal carcinoma of the breast who underwent primary surgical resection (radical mastectomy, modified radical mastectomy, total mastectomy, or segmental) for the years 1983 to 2002. Demographic, clinical, and pathologic data were culled and analyzed to determine the impact of radiation therapy (RT) following resection. Survival rates were estimated using the Kaplan-Meier method and significance was determined using the log-rank test (P<0.05). Multivariate analysis with the Cox proportional hazards model was performed to determine factors significant for overall (OS) and cause-specific survival (CSS).

A total of 1337 patients met the eligibility criteria and were analyzed. Median follow-up was 7.3 years (range, 1 mo to 25 y). Most men underwent modified radical mastectomy (n=1062) with a minority undergoing segmental (n=113). About 329 men received postoperative external beam RT. The median rates of OS and CSS for all men were 10.5 years and not yet reached, respectively. The surgical procedure did not significantly associate with OS or CSS. By stage, RT was associated with improved OS for stage I (P=0.03). There was a trend for improved survival with stage II (P=0.21) and III (P=0.15). RT was not associated with improved CSS by stage. RT improved rates of OS and CSS in N2 patients without reaching statistical significance (P=0.10 and 0.22). On multivariate analysis, advancing age, stage and grade, and no postoperative RT predicted for worse OS. However, when controlled for those with known hormone receptor status (n=978), only the factors of advancing age, stage, grade, and hormone receptor negativity predicted for worse OS. Advancing age, stage, and grade were the only predictors of CSS irrespective of the cohort analyzed.

The primary surgical procedure did not ultimately influence OS or CSS in this population-based registry of males with breast cancer. A statistically nonsignificant improvement with postoperative RT was observed in men with lymph node involvement, larger tumor size, or higher stage. When controlled for age, stage, and grade in multivariate analysis, postoperative RT predicted for improved OS but not CSS. These data suggest a beneficial effect of RT in the postoperative setting. A prospective study is necessary to further elucidate appropriate treatment strategies for men with breast cancer.