Comparative epidemiology of breast cancer among men and women in the US, 1996 to 2000

Abstract

Objective: Few investigations of breast cancer among men have been conducted because of the relative rarity of this malignancy. The objective of this analysis was to compare the demographic, pathological, and clinical features of breast cancer among men and women.

Methods: Breast cancer among 6379 men and 744,275 women was identified through 34 US population-based registries in the US during the period 1996 to 2000. These registries were estimated to represent 69% of the US population. Age-adjusted incidence rates (AAIR) were calculated per million population using counts derived from the 2000 US census.

Results: The AAIR of breast cancer among men (16.6) was substantially lower than the incidence among women (1557.7). Rates of breast cancer among black men were higher than among white and Asian-Pacific Island men, in contrast to women among whom rates in whites exceeded those among other ethnic groups. Similar to women, breast cancer rates among non-Hispanic men were 50% greater than among Hispanic men. Ductal cancer was the most common histologic type diagnosed in both sexes. The incidence of lobular cancer was rare in men, but Paget's disease and papillary carcinoma occurred with lower relative frequency in women than in men. Lobular breast cancers were less common among black men and women than among other ethnic groups. In situ breast cancer was diagnosed in 10.8% of men and 16.2% of women. Localized breast cancer was the most common stage at diagnosis in both sexes and all ethnic groups, although women were more likely than men to be diagnosed at a localized stage. Cancer was 10% more likely to be diagnosed in the left breast than the right breast among men compared to 4% in women.

Conclusions: In spite of the rare incidence of breast cancer in men, the descriptive epidemiology of this malignancy is surprisingly similar to that in women. An explanation for the greater relative incidence of breast cancer in black men is a research challenge.