EPIDEMIOLOGIC-STUDY OF BREAST-CANCER AND BENIGN BREAST NEOPLASIAS IN RELATION TO THE ORAL-CONTRACEPTIVE AND ESTROGEN USE

A case-control study was conducted of oral contraceptive and other estrogen use in patients with malignant or benign breast disease of ages less than 65 yr. Ever usage of oral contraceptive and estrogens was slightly less common among breast cancer patients up to 49 yr of age as compared to their controls. No difference in estrogen use was seen in older patients. Significantly lower rates of oral contraceptive ever- and long-term (for 2 yr or more) users were found among cystic disease cases; this was not seen in fibroadenoma cases. Among patients with cystic disease and fibroadenoma, there was a considerably higher proportion of ever pregnant and ever parous. Menopausal women were less frequent than expected among cystic disease patients. Other factors ordinarily associated with breast cancer were not found to be associated with benign breast neoplasias. © 1979.