This study aims to reduce the burden of cancer by influencing adherence to standards of cancer care for female breast cancer and by better understanding patterns of care for prostate cancer. Disparities in cancer treatment that are identified in the Minnesota component of this study will inform interventions undertaken by the Minnesota Cancer Alliance, the public-private collaboration implementing the state's comprehensive cancer control plan. Cancer Plan Minnesota has identified reducing disparities in cancer treatment as a top priority. This study addresses the goals of CDC-supported research by improving cancer control and enhancing the health of persons diagnosed with two common cancers. The specific objectives of this study are to develop and implement a standardized protocol which will 1) evaluate the quality of data on stage at diagnosis and first course of treatment on a representative sample of eligible invasive female breast and prostate cancers reported to each of the selected registries, 2) collect additional information from the medical records of reabstracted cases which may not be routinely abstracted but which has been shown to influence treatment received (e.g., comorbid illnesses, type of insurance, method of detection, diagnostic workup, and family history of cancer), 3) analyze the enhanced data to determine the proportion of persons diagnosed with these cancers who received the recommended standard of therapy, or, for prostate cancer, different treatment modalities, and assess the determinants of receiving quality care (e.g., race/ethnicity, urban/rural residence, insurance status, and publicly available information on hospital and provider characteristics) in each of the selected registries, and 4) combine data from all selected registries to assess data quality and cancer treatment for these two common cancer sites in the selected registries. This application proposesto reabstract clinical information on 2,500 Minnesota women diagnosed with Stage I, II, or III breast cancer and 2,500 men diagnosed with prostate cancer during 2004 (non-Hispanic white) or 2003-2005 (not non-Hispanic white). Results of consolidated reabstracteddata on stage at diagnosis and treatment received will be compared to originally abstracted data to determine data quality. Simple descriptive statistics will be used to describe treatment received. Logistic regression will be used to evaluate determinants of treatment received and identify disparities. Findings will be disseminated through presentations and papers.