BREAST-CANCER - FACTORS ASSOCIATED WITH STAGE AT DIAGNOSIS IN BLACK-AND-WHITE WOMEN

Background: Numerous studies have reported differences in cancer stagi ng at diagnosis and in survival between Black and White patients with breast cancer. Utilizing data obtained from the National Cancer Instit ute's (NCI's) Black/White Cancer Survival Study for the period 1985-19 86, a new study is presented here that systematically examines multipl e explanatory factors (e.g., lack of mammograms) associated with these cancer-staging differences. Purpose: We evaluated within a single stu dy the relationship of selected demographic, lifestyle, antecedent med ical experiences, and health care acces s factors to cancer staging at diagnosis in Black and White breast cancer patients. Methods: Data ut ilized in this population-based cohort study of 1222 eligible women (6 49 Black and 573 White) newly diagnosed for the period 1985-1986 with histologically confirmed primary breast cancer were obtained from the NCI's Black/White Cancer Survival Study. Sources of data included abst racts of hospital medical records, central review of histology slides by a study consultant pathologist, and patient interviews obtained fro m three metropolitan areas: Atlanta, New Orleans, and San Francisco-Oa kland. Within each area, 70% of all Black incident cases were randomly selected, and a sample of White cases, frequency matched by age group s (20-49 years, 50-64 years, and 65-79 years), was selected for compar ison. Stage of breast cancer at diagnosis was classified according to the international tumor-lymph node-metastases (TNM) system. Statistica l models utilized in this study included the log-linear and polychotom ous logistic regression with multiple predictor variables. Results: Fa ctors associated with cancer staging were differentially expressed in Blacks and Whites. Indicators of access to health care, a lack of mamm ograms, and an increased body mass index significantly (P<.02) contrib uted to stage differences in Blacks, whereas income was marginally ass ociated (P = .06) with stage for Whites only. Nuclear grade, having a breast examination by a physician, and a history of patient delay expl ained approximately 50% of the excess risk for stage III-IV Cancer ver sus stage I-II(N0) cancer among Blacks compared with Whites (odds rati o- reduction from 2.19 to 1.68). Conclusion: These findings suggest th at no single factor or group of factors can explain more than half of the race-stage differences noted in this study with respect to Black a nd White breast cancer patients.