Independent risk factors of benign and malignant breast lesions.

The purpose of this study is to evaluate the risk factors of benign breast disease and to compare them with the known risk factors of breast cancer in order to make inferences on the relationship between benign breast disease and breast cancer. All benign breast lesions diagnosed from the population of the city of Tampere, Finland in 1974-1977 were reclassified by two pathologists into two groups of dysplasias and two groups of tumors. In the risk analysis of 422 age-matched pairs no group of benign lesions had risk factors consistently similar to those of breast cancer. It is therefore likely that either benign breast disease is not associate with breast cancer or it is an independent risk factor, not associated with the other high risk indicators of breast cancer.