Estrogens and endometrial carcinoma

Abstract

A group of 205 women with endometrial carcinoma was matched for age, parity, and year of operation with a group of 205 women who had had hysterectomies for benign disease. In the former group, 32 patients had used conjugated estrogens, while in the latter group 12 had used this hormone, yielding a relative risk of 3.1 (P = 0.0008). Users of other forms of systemic estrogens showed similar elevations in relative risk. Relative risk was related to duration of use, progressing from no evidence of risk among those using the hormone for less than 5 years to an 11.5-fold greater risk for those using it for 10 years or more. Risk was also related to the strength of the medication. The relative risk for users of the 1.25-mg tablets was 12.7 as compared to a two- to fourfold greater risk among users of lesser strength tablets.

PIP: 205 patients with endometrial carcinoma, excluding carcinoma in situ, were seen in 1 private practice between 1947-1976. A control for each case was chosen from patients who had had a hysterectomy for a benign condition. Average age of patients with cancer was 56.5 years and parity 1.5. The cancer patients weighed significantly more than controls. A history of diabetes was recorded for 8 study patients, and 1 control. Of the 205 cancer patients, 55, and of the control patients, 31, had used some form of estrogen-containing medication. The relative risk (RR) for all users of systemic estrogens was 2.6. Most had used conjugated estrogens giving an RR of 3.1 for this form of the drug. There was no increased risk associated with vaginal estrogenic preparations or oral contraceptives. The RR increased with increasing duration of use, with no appreciable increase in the risk for those using the medication for less than 5 years. Those using these drugs for 5-9 years had a risk 11.5 times that of nonusers. Those using the 1.25 mg tablet had a risk markedly above that for users of the .3 or .625 mg tablets. The study group had more frequent histories of abnormal uterine bleeding than the control group. The lifetime risk of developing endometrial cancer is estimated as 2.2% for whites and 1.1% for blacks. A 70.9% 5-year survival rate and a 55.8% 10-year survival rate have been recorded. With early diagnosis, the cure rate may approach 95%. Many of the symptoms of women in the manopause may be alleviated by estrogenic therapy. Many of these women will have had a hysterectomy and no longer be at risk of endometrial cancer. Therefore, such therapy seems justified.