Geographic variation in racial differences in breast cancer incidence among young women

MN Fouad MD MPH^a, CP Mayo PhD^a, D Carey PhD^a, EM Funkhouse DrPH PhD, CI Kiefe MD PhD^a, EE Partridge MD^a, RJ Wilson MPH^b

^aUniversity of Alabama at Birmingham, , ^bAlabama Dept. Public Health

AIM: Racial disparities in breast cancer incidence among women age 25-39 have been noted; however, insufficient attention has been given to geographic influence on the magnitude of these differences. The purpose of this study was to examine the magnitude of these ethnic differences and to determine whether geographic region had any influence on them. METHODS: Using raw data collected by the Surveillance Epidemiology and End Results (SEER), and Alabama state cancer registry, We compared age-specific incidence rate, and stage at diagnosis for African American and White women, by SEER region and Metro Alabama, for 1996-1998. We examined the magnitude of racial differences in breast cancer incidence rates and relative risk across regions, and compared geographic variation of incidence rates within race. Study Population :A total of 8734 women (1442 African American, 7292 White), age 25-39, diagnosed 1996-1998, residing in 11 SEER regions and in metropolitan Alabama (MetroAL = Jefferson + Mobile counties). . RESULTS: In all SEER regions and Metro Alabama, African American women had higher incidence rate (IR) than white women, with the magnitude of the disparity being greatest in the South: MetroAL-BIR= 60.3 vs.WIR= 30.8; ATL-BIR= 45.4 vs.WIR= 36.2; LA-BIR= 38.3 vs.WIR= 30.3; DET-BIR= 39.4 vs.WIR= 38.8, SEER remaining regions combined = 38.5 vs. 37.2 . Within race, the regional variability was much more pronounced among African American women, with higher incidence rates in the South for African American (but not white) women. CONCLUSIONS: Young African American women had significantly increased breast cancer incidence in the South, a regional variability that was not observed in white women and explained markedly by higher racial disparities in the South. IMPLICATIONS FOR CANCER PREVENTION & EARLY DETECTION: Further research needs to identify causes of the regional effect on African Americans but not whites, and develop methods and programs to address the resulting racial disparities.

Paper presented at the International Symposium on Predictive Oncology and Intervention Strategies; Nice, France; February 7 - 10, 2004; in oral session 891 (Risk factors).