title: Predicting risk of breast cancer in postmenopausal women by hormone receptor status.
abstract: BACKGROUND
  Strategies for estrogen receptor (ER)-positive breast cancer risk reduction in postmenopausal women require screening of large populations to identify those with potential benefit. We evaluated and attempted to improve the performance of the Breast Cancer Risk Assessment Tool (i.e., the Gail model) for estimating invasive breast cancer risk by receptor status in postmenopausal women.
  
  
  METHODS
  In The Women's Health Initiative cohort, breast cancer risk estimates from the Gail model and models incorporating additional or fewer risk factors and 5-year incidence of ER-positive and ER-negative invasive breast cancers were determined and compared by use of receiver operating characteristics and area under the curve (AUC) statistics. All statistical tests were two-sided.
  
  
  RESULTS
  Among 147,916 eligible women, 3236 were diagnosed with invasive breast cancer. The overall AUC for the Gail model was 0.58 (95% confidence interval [CI]=0.56 to 0.60). The Gail model underestimated 5-year invasive breast cancer incidence by approximately 20% (P<.001), mostly among those with a low estimated risk. Discriminatory performance was better for the risk of ER-positive cancer (AUC = 0.60, 95% CI = 0.58 to 0.62) than for the risk of ER-negative cancer (AUC = 0.50, 95% CI = 0.45 to 0.54). Age and age at menopause were statistically significantly associated with ER-positive but not ER-negative cancers (P=.05 and P=.04 for heterogeneity, respectively). For ER-positive cancers, no additional risk factors substantially improved the Gail model prediction. However, a simpler model that included only age, breast cancer in first-degree relatives, and previous breast biopsy examination performed similarly for ER-positive breast cancer prediction (AUC=0.58, 95% CI= 0.56 to 0.60); postmenopausal women who were 55 years or older with either a previous breast biopsy examination or a family history of breast cancer had a 5-year breast cancer risk of 1.8% or higher.
  
  
  CONCLUSIONS
  In postmenopausal women, the Gail model identified populations at increased risk for ER-positive but not ER-negative breast cancers. A model with fewer variables appears to provide a simpler approach for screening for breast cancer risk.
authors.affiliation: Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, 1124 West Carson Street, Torrance, CA 90502, USA. rchlebowski@gmail.com
authors.forename: Rowan T
authors.initials: RT
authors.lastname: Chlebowski
authors.forename: Garnet L
authors.initials: GL
authors.lastname: Anderson
authors.forename: Dorothy S
authors.initials: DS
authors.lastname: Lane
authors.forename: Aaron K
authors.initials: AK
authors.lastname: Aragaki
authors.forename: Thomas
authors.initials: T
authors.lastname: Rohan
authors.forename: Shagufta
authors.initials: S
authors.lastname: Yasmeen
authors.forename: Gloria
authors.initials: G
authors.lastname: Sarto
authors.forename: Carol A
authors.initials: CA
authors.lastname: Rosenberg
authors.forename: F Allan
authors.initials: FA
authors.lastname: Hubbell
mesh_terms: D000368:Aged; D000428:Alcohol Drinking / Q000009:adverse effects; D019540:Area Under Curve; D014408:Biomarkers, Tumor / Q000032:analysis*; D001706:Biopsy; D001835:Body Weight; D001943:Breast Neoplasms / Q000737:chemistry* / Q000453:epidemiology* / Q000208:ethnology / Q000209:etiology; D018270:Carcinoma, Ductal, Breast / Q000737:chemistry / Q000453:epidemiology; D015986:Confounding Factors, Epidemiologic; D005006:Ethnicity / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D016015:Logistic Models; D008875:Middle Aged; D015233:Models, Statistical; D009043:Motor Activity; D015999:Multivariate Analysis; D016017:Odds Ratio; D017698:Postmenopause; D011237:Predictive Value of Tests; D012372:ROC Curve; D011960:Receptors, Estrogen / Q000032:analysis*; D017584:Reproductive History; D018570:Risk Assessment; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects; D011795:Surveys and Questionnaires; D014481:United States / Q000453:epidemiology; D016387:Women's Health
chemical_list: D014408:Biomarkers, Tumor; D011960:Receptors, Estrogen