Projecting individualized absolute invasive breast cancer risk in African American women.
BACKGROUND
The Breast Cancer Risk Assessment Tool of the National Cancer Institute (NCI) is widely used for counseling and determining eligibility for breast cancer prevention trials, although its validity for projecting risk in African American women is uncertain. We developed a model for projecting absolute risk of invasive breast cancer in African American women and compared its projections with those from the Breast Cancer Risk Assessment Tool.


METHODS
Data from 1607 African American women with invasive breast cancer and 1647 African American control subjects in the Women's Contraceptive and Reproductive Experiences (CARE) Study were used to compute relative and attributable risks that were based on age at menarche, number of affected mother or sisters, and number of previous benign biopsy examinations. Absolute risks were obtained by combining this information with data on invasive breast cancer incidence in African American women from the NCI's Surveillance, Epidemiology and End Results Program and with national mortality data. Eligibility screening data from the Study of Tamoxifen and Raloxifene (STAR) trial were used to determine how the new model would affect eligibility, and independent data from the Women's Health Initiative (WHI) were used to assess how well numbers of invasive breast cancers predicted by the new model agreed with observed cancers.


RESULTS
Tables and graphs for estimating relative risks and projecting absolute invasive breast cancer risk with confidence intervals were developed for African American women. Relative risks for family history and number of biopsies and attributable risks estimated from the CARE population were lower than those from the Breast Cancer Risk Assessment Tool, as was the discriminatory accuracy (i.e., concordance). Using eligibility screening data from the STAR trial, we estimated that 30.3% of African American women would have had 5-year invasive breast cancer risks of at least 1.66% by use of the CARE model, compared with only 14.5% by use of the Breast Cancer Risk Assessment Tool. The numbers of cancers predicted by the CARE model agreed well with observed numbers of cancers (i.e., it was well calibrated) in data from the WHI, except that it underestimated risk in African American women with breast biopsy examinations.


CONCLUSIONS
The CARE model usually gave higher risk estimates for African American women than the Breast Cancer Risk Assessment Tool and is recommended for counseling African American women regarding their risk of breast cancer.
Gail
Mitchell H
MH
Division of Cancer Epidemiology and Genetics, National Cancer Institute, Executive Plaza South Rm 8032, Bethesda, MD 20892-7244, USA. gailm@mail.nih.gov
Costantino
Joseph P
JP
Pee
David
D
Bondy
Melissa
M
Newman
Lisa
L
Selvan
Mano
M
Anderson
Garnet L
GL
Malone
Kathleen E
KE
Marchbanks
Polly A
PA
McCaskill-Stevens
Worta
W
Norman
Sandra A
SA
Simon
Michael S
MS
Spirtas
Robert
R
Ursin
Giske
G
Bernstein
Leslie
L
D000328:Adult; D001741:Black or African American / Q000706:statistics & numerical data*; D000368:Aged; D018931:Antineoplastic Agents, Hormonal / Q000627:therapeutic use; D001706:Biopsy; D001943:Breast Neoplasms / Q000453:epidemiology* / Q000401:mortality / Q000517:prevention & control; D018270:Carcinoma, Ductal, Breast / Q000453:epidemiology* / Q000401:mortality / Q000517:prevention & control; D015986:Confounding Factors, Epidemiologic; D020847:Estrogen Receptor Modulators / Q000627:therapeutic use; D005260:Female; D005544:Forecasting; D006801:Humans; D015994:Incidence; D016015:Logistic Models; D008327:Mammography; D008403:Mass Screening / Q000379:methods; D008875:Middle Aged; D016017:Odds Ratio; D020849:Raloxifene Hydrochloride / Q000627:therapeutic use; D018570:Risk Assessment; D018426:SEER Program; D013629:Tamoxifen / Q000627:therapeutic use; D014481:United States / Q000453:epidemiology; D016387:Women's Health
D018931:Antineoplastic Agents, Hormonal; D020847:Estrogen Receptor Modulators; D013629:Tamoxifen; D020849:Raloxifene Hydrochloride