CLINICAL AND BIOLOGIC PROGNOSTIC FACTORS IN BREAST-CANCER DIAGNOSED DURING POSTMENOPAUSAL HORMONE REPLACEMENT THERAPY

Objective: To ascertain the influence of hormone replacement therapy o n clinical and biologic prognostic factors of breast cancer. Methods: Between 1976-1992, we treated 1081 postmenopausal women for breast can cer at our institution. Of these, 68 were undergoing postmenopausal ho rmone replacement therapy at the time of diagnosis. These patients wer e compared with a matched control group of 272 breast cancer patients who had not undergone prior hormone replacement therapy. Results: Pati ents who developed breast cancer during hormone replacement therapy ha d fewer locally advanced cancers (large tumors and extensive lymph nod e involvement) and more well-differentiated cancers (infiltrating lobu lar cancers and grade 1 cancer). The number of patients with estradiol or progesterone receptors was lower in the hormone-treated group. Met astasis-free survival curves showed a tendency (P = .05) for better pr ognosis in hormone-treated patients both overall and in stage T2. Conc lusions: Hormone replacement therapy per se does not affect the progno sis of breast cancer. Regular surveillance during hormone replacement therapy reduces the number of locally advanced cancers and thus improv es the survival rate. The higher number of well-differentiated cancers and the distribution of hormone receptivity may reflect interaction b etween neoplastic tissue and exogenous hormones.