CASE-CONTROL STUDY OF ORAL-CONTRACEPTIVE PILLS AND ENDOMETRIAL CANCER

As part of a large case-control investigation of the association between estrogens and endometrial cancer, we have collected and analyzed data about the use of estrogen estrogens preparations, as noted during personal interviews of all the available cases and controls. The results from this analysis do not support an association between the use of oral contraceptive pills and endometrial cancer. This conclusion is strengthened by the consistency of the results in two separate case-control studies done with different methods of patient selection. The data seem to indicate, therefore, that no association exists between the use of oral contraceptive pills and the subsequent development of endometrial cancer.; This paper analyses the data of a large case-control study on the relationship of various estrogen preparations to endometrial cancer. 2 methods of selecting cases and controls (conventional and alternative) were used. In both the conventional and alternative series, mean age of the cases was 60 + or - 8 (SD); for controls of both series, mean age was 61 + or - 8 (SD). In the conventional series. 119 cases from the Yale Registry Tumor between July '74 and June '76 were age-matched (within 4 years) with 119 controls. In the alternative series, 149 who had had dilatation and curettage or hysterectomy between January '74 and June '76 were age-matched with 149 controls. All case and control members were directly interviewed by telephone and were asked as to type of oral contraceptive used, duration of use, and reasons for prescription and discontinuation. In the conventional series, exposure rate, or number of women who were pill users, was 6% for cases and controls; the odds ratio was 1.0. In the alternative series, exposure rate was 8% for cases and controls, with an odds ratio of 0.95. Results of this analysis failed to support the association between oral contraceptive use and endometrial cancer, and this was further strengthened by the consistency of results in 2 separate case control investigations done with different methods of patient selection.