There were three intriguing results. Age-specific incidence patterns showed that the biology of male breast cancer resembled that of late-onset female breast cancer. Similar breast cancer incidence trends among men and women suggested that there are common breast cancer risk factors that affect both sexes, especially estrogen receptor-positive breast cancer. Finally, breast cancer mortality and survival rates have improved significantly over time for both male and female breast cancer, but progress for men has lagged behind that for women.

Our pooled analysis demonstrated that African American ethnicity is a significant and independent predictor of poor outcome from breast cancer, even after accounting for socioeconomic status by conventional measures. These findings support the need for further investigation of the biologic, genetic, and sociocultural factors that may influence survival in African American patients with breast cancer.