Abstract

PIP: Because of adverse publicity regarding increased risk of endometrial cancer in women receiving estrogen therapy, a 2-year prospective study was conducted in 1976 to determine the incidence of endometrial cancer in postmenopausal women. A retrospective study for the year 1975 was also added. A postmenopausal survey card for each patient recorded the patient's visit and clinical data, as well as hormone therapies (estrogen, progestogen, androgen). Postmenopausal women never treated with hormones were also provided survey cards. A total of 2088 patient-years of estrogen use was recorded during the combined 3-year study period (1975-77). 8 of the estrogen users had a diagnosis of adenocarcinoma of the endometrium for an annual incidence rate of 3.8/1000 women. 2 endometrial cancers were detected in the estrogen-progestogen users for a cancer incidence rate of 0.5/1000 (3792 patient-years of observation); this finding suggests that progestogen provides better protection against endometrial cancer compared to estrogens. This difference between estrogen users and estrogen-progestogen users was statistically significant (p ? 0.01). 1 endometrial malignancy occurred among estrogen vaginal cream users, giving an incidence of 1.7/1000. The patient used Premarin vaginal cream (1 gm thrice weekly) for 7 months before the cancer was diagnosed. No endometrial cancer was diagnosed in both the progestogen and androgen groups. Overall, 14 endometrial cancers out of 8170 years of observation were diagnosed in this clinic; annual incidence rate for the study period was 1.7/1000. 199 women with endometrial hyperplasia (a precancerous lesion) were treated with progestogens for 3 to 6 months. The hyperplastic endometrium returned to normal in 96.5%. It was suggested that all postmenopausal women with intact uterus be given the Progestogen Challenge Test and that progestogens be given to the women each month as long as bleeding follows. This should prevent the development of endometrial cancer in most women.