Endometrial cancer in postmenopausal women with and without previous estrogen replacement treatment: comparison of clinical and histopathological characteristics.

Clinical and histopathological features of postmenopausal endometrial cancer were studied in 63 patients who had received exogenous estrogens previously and in 76 patients who had never been exposed to estrogens. All treatments were primarily surgical. Estrogen users were younger than nonusers (P < 0.001). Body mass index, age at menarche and menopause, parity, and blood pressure were comparable in the two groups. Prevalence of diabetes mellitus was higher in nonusers (P < 0.01). Tumor stage was earlier (P < 0.001) and the histologic grade was lower (P < 0.001) in estrogen users compared to nonusers, and the frequency of clear cell and adenosquamous carcinoma was lower in estrogen users. Myometrial invasion was less pronounced in estrogen users, independently of grade and stage (P < 0.01). Number of mitoses correlated significantly with grade and with estrogen use. Features such as squamous metaplasia and "foam" cells were not related to tumor grade or use of estrogens. The receptor content correlated inversely with grade but was not related to estrogen use. Duration of estrogen treatment was not associated with tumor stage and grade. Our findings support the theory that endometrial cancer of estrogen users may be less aggressive than cancer of nonusers.