In contrast to first primary breast cancers, second primary breast cancers are more common in Black than in White women

BACKGROUND: Breast cancer incidence increases with age and exhibits a Black-to-White crossover around age 40. Breast cancer survivors are at a significantly elevated risk of developing a second primary breast compared with the general population. The purpose of this study was to determine whether a similar crossover occurs in second primary breast in Black and White women. METHODS: The Surveillance, Epidemiology, and End Results' Registry 9 was used to follow 415,664 White and 39,887 Black female breast cancer survivors, diagnosed at age 19 or older, for a second primary breast cancer between 1973 and 2007. Cumulative incidence curves were generated; Pepe and Mori's test was used to test for significance. RESULTS: Second primary breast cancer followed the incidence pattern of the first primary breast cancer in Black and White women diagnosed before age 45. It was opposite of the pattern of first primary breast cancer in Black and White women diagnosed at age 45 or later. CONCLUSION: Despite the Black-to-White crossover of first primary breast cancer around age 40, the incidence of second primary breast cancer does not appear affected by the age at diagnosis of the first primary. *Role of the presenting author: This abstract represents part of my doctoral dissertation research at GWU. I conceived and designed the study, performed the data analysis and interpretation, and drafted the manuscript.