Geographic patterns of advanced breast cancer in Los Angeles: associations with biological and sociodemographic factors (United States).

OBJECTIVE: Examination of patterns of advanced breast cancer may provide evidence needed to direct health care resources to those communities or population groups in greatest need. We assessed to what degree biologic, ethnic, and sociodemographic factors could explain such patterns within Los Angeles County.
METHODS: The proportion of cases of advanced disease among all breast cancer cases identified during 1992-1996 were analyzed using generalized linear mixed models with random census tract effects. Models included characteristics of the individual and her tumor, census tract of residence, and aggregated health districts.
RESULTS: Approximately 6% of cases, ranging from 4% for Asian to 10% for Black women, were diagnosed as advanced, exhibiting striking geographic patterns. Tumor histology and hormone receptor status were most predictive of advanced disease. Sociodemographic variables such as marital status, median income, and distance to nearest mammography unit showed additional association with risk.
CONCLUSIONS: These models explain most of the geographical patterns and eliminate differences between White and Hispanic but not Asian or Black women, identify subpopulations at high risk of advanced disease, and suggest cancer control opportunities.