Proposal to decrease the risk and improve the prognosis of breast cancer

Of 256 patients with breast cancer diagnosed between 1972 and 1981, 102 have died (mortality, 39.8%). More hormone users had negative axillary nodes (57.1%) than did nonusers (41.8%). The mortality of the hormone users (22.2%) was significantly lower (p less than or equal to 0.01) than that of the nonusers (45.5%). In 162 patients whose diagnosis of breast cancer was made prior to 1979, the 5-year survival rate in hormone users was 76.2% compared to 48.1% in nonusers. During the prospective phase of the study from 1975 to 1981, the lowest incidence of breast carcinoma (67.3:100,000) was observed in the estrogen-progestogen users and was significantly lower than that of the untreated group (342.3:100,000) and lower than that expected from both the Third National Cancer Survey and the National Cancer Institute System for Electronic Evaluation and Retrieval (SEER) data (p less than or equal to 0.01). Estrogen therapy does not increase the risk of mammary malignancy, but added progestogen significantly decreases the risk.