Clinical Characteristics of Breast Cancers in African-American Women with Benign Breast Disease: A Comparison to the Surveillance, Epidemiology, and End Results Program

Benign breast disease (BBD) is a very common condition, diagnosed in approximately half of all American women throughout their lifecourse. White women with BBD are known to be at substantially increased risk of subsequent breast cancer; however, nothing is known about breast cancer characteristics that develop after a BBD diagnosis in African-American women. Here, we compared 109 breast cancers that developed in a population of African-American women with a history of BBD to 10,601 breast cancers that developed in a general population of African-American women whose cancers were recorded by the Metropolitan Detroit Cancer Surveillance System (MDCSS population). Demographic and clinical characteristics of the BBD population were compared to the MDCSS population, using chi-squared tests, Fisher's exact tests, t-tests, and Wilcoxon tests where appropriate. Kaplan-Meier curves and Cox regression models were used to examine survival. Women in the BBD population were diagnosed with lower grade (p=0.02), earlier stage cancers (p=0.003) that were more likely to be hormone receptor-positive (p=0.03) compared to the general metropolitan Detroit African-American population. In situ cancers were more common among women in the BBD cohort (36.7%) compared to the MDCSS population (22.1%, p<0.001). Overall, women in the BBD population were less likely to die from breast cancer after 10years of follow-up (p=0.05), but this association was not seen when analyses were limited to invasive breast cancers. These results suggest that breast cancers occurring after a BBD diagnosis may have more favorable clinical parameters, but the majority of cancers are still invasive, with survival rates similar to the general African-American population.