Characterizing lobular carcinoma of the male breast using the SEER database.

Background: Lobular carcinoma of the male breast is rare. We sought to investigate the clinical characteristics, treatment, and outcomes of men and women with lobular breast cancer, using a population-based database.

Methods: We reviewed the Surveillance, Epidemiology, and End Results database 1988-2008 and identified patients with a lobular breast cancer diagnosis (invasive lobular carcinoma [ILC] and lobular carcinoma in situ [LCIS]) using the "International Classification of Diseases for Oncology, Third Edition" codes. Bivariate analyses compared the male and female patients on demographics, clinical characteristics, and treatment modalities. Multivariate logistic regression analysis determined the risk-adjusted likelihood of receiving treatment. Survival analysis was done and hazard ratios were obtained using Cox proportional models.

Results: Overall, 133,339 patients were identified, including 133,168 women (99.9%) and 171 men (0.1%). Most had ILC (82.08%). The median age was 66 ± 20 y for the men and 61 ± 21 y for the women. The men with ILC were more likely to have poorly differentiated tumors (26.45% versus 15.61%; P < 0.001) and stage IV disease (9.03% versus 4.18%; P = 0.005) than were the women. The cancer-specific 5-year survival rates for ILC were 82.9% for the men and 91.9% for the women. Adjusted survival was better for patients with ILC receiving surgery plus radiotherapy than patients receiving neither (hazard ratio 0.52, 95% confidence interval 0.49-0.56). Women with ILC had a 55% increased odds of receiving surgery plus radiotherapy compared with men (odds ratio 1.55, 95% confidence interval 1.08-2.22).

Conclusions: ILC presents at a higher grade and stage in men. The difference in disease characteristics and survival rates suggests that the treatment of men with lobular breast cancer should be adjusted to improve their outcomes.