title: Evaluating breast cancer risk projections for Hispanic women.
abstract: For Hispanic women, the Breast Cancer Risk Assessment Tool (BCRAT; "Gail Model") combines 1990-1996 breast cancer incidence for Hispanic women with relative risks for breast cancer risk factors from non-Hispanic white (NHW) women. BCRAT risk projections have never been comprehensively evaluated for Hispanic women. We compared the relative risks and calibration of BCRAT risk projections for 6,353 Hispanic to 128,976 NHW postmenopausal participants aged 50 and older in the Women's Health Initiative (WHI). Calibration was assessed by the ratio of the number of breast cancers observed with that expected by the BCRAT (O/E). We re-evaluated calibration for an updated BCRAT that combined BCRAT relative risks with 1993-2007 breast cancer incidence that is contemporaneous with the WHI. Cox regression was used to estimate relative risks. Discriminatory accuracy was assessed using the concordance statistic (AUC). In the WHI Main Study, the BCRAT underestimated the number of breast cancers by 18% in both Hispanics (O/E = 1.18, P = 0.06) and NHWs (O/E = 1.18, P < 0.001). Updating the BCRAT improved calibration for Hispanic women (O/E = 1.08, P = 0.4) and NHW women (O/E = 0.98, P = 0.2). For Hispanic women, relative risks for number of breast biopsies (1.71 vs. 1.27, P = 0.03) and age at first birth (0.97 vs. 1.24, P = 0.02) differed between the WHI and BCRAT. The AUC was higher for Hispanic women than NHW women (0.63 vs. 0.58, P = 0.03). Updating the BCRAT with contemporaneous breast cancer incidence rates improved calibration in the WHI. The modest discriminatory accuracy of the BCRAT for Hispanic women might improve by using risk factor relative risks specific to Hispanic women.
authors.affiliation: School of Public Health, Department of Health Services, University of Washington, Box 357660, Seattle, WA 98195, USA. mbanegas@fhcrc.org
authors.forename: Matthew P
authors.initials: MP
authors.lastname: Banegas
authors.forename: Mitchell H
authors.initials: MH
authors.lastname: Gail
authors.forename: Andrea
authors.initials: A
authors.lastname: LaCroix
authors.forename: Beti
authors.initials: B
authors.lastname: Thompson
authors.forename: Maria Elena
authors.initials: ME
authors.lastname: Martinez
authors.forename: Jean
authors.initials: J
authors.lastname: Wactawski-Wende
authors.forename: Esther M
authors.initials: EM
authors.lastname: John
authors.forename: F Allan
authors.initials: FA
authors.lastname: Hubbell
authors.forename: Shagufta
authors.initials: S
authors.lastname: Yasmeen
authors.forename: Hormuzd A
authors.initials: HA
authors.lastname: Katki
mesh_terms: D019540:Area Under Curve; D001943:Breast Neoplasms / Q000453:epidemiology*; D002138:Calibration; D005260:Female; D006630:Hispanic or Latino; D006801:Humans; D015994:Incidence; D008875:Middle Aged; D008954:Models, Biological; D016016:Proportional Hazards Models; D018570:Risk Assessment / Q000379:methods; D012307:Risk Factors; D014481:United States / Q000453:epidemiology