Determine the specific risk of an individual patient, or group of patients, given specific information about anatomic changes in the breast as well as non-anatomic risk factors. Identification of anatomic risk factors at a given point in time with extended follow-up of the patients showing different changes is the most definitive available method for specific assignment of risk. This study design, allowing comparison of the incidence of subsequent breast cancer in women with cinfirmed benign lesions and appropriate control group(s) is essentially a prospective study as women enter the study with a finding 10-25 years prior to the time of follow-up. This is a prospective study conducted in retrospect. Neither the case-control comparison of the frequency of types of breast disease in women who developed cancer nor the study of concurrent changes found in breasts containing carcinomas may achieve the aim proposed by this study.