Black-White Breast Cancer Incidence Trends: Effects of Ethnicity

Recent reports of converging black and white breast cancer incidence rates have gained much attention, potentially foreshadowing a worsening of the black-white breast cancer mortality disparity. However, these incidence rates also reflect the sum of non-Hispanics and Hispanics that may mask important ethnicity-specific trends. We therefore assessed race- and ethnicity-specific breast cancer trends using the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) 13 Registries Database (1992-2014). Age-period-cohort models projected rates for 2015-2030. Results confirmed merging of age-standardized incidence rates for blacks and whites circa 2012, but not for non-Hispanic black (NHB) and non-Hispanic white (NHW) women. Incidence rates were highest for NHW women (n = 382 290), followed by NHB women (n = 51 074), and then Hispanic white women (n = 48 651). The sample size for Hispanic blacks was too small for analysis (n = 693). Notably, future incidence rates are expected to slowly increase (2015 through 2030) among NHW women (0.24% per year, 95% confidence interval [CI] = 0.17 to 0.32) and slowly decrease for NHB women (-0.14% per year, 95% CI = -0.15 to -0.13). A putative worsening of the black-white mortality disparity, therefore, seems unlikely. Ethnicity matters when assessing race-specific breast cancer incidence rates.