Estrogen plus Progestin and Colorectal Cancer in Postmenopausal Women

In the Women's Health Initiative trial, postmenopausal women who were randomly assigned to take estrogen plus progestin were found to have a lower risk of colorectal cancer than women who were assigned to take placebo. However, the cancers that were found in the hormone group were more advanced than those that were found in the placebo group. Postmenopausal women assigned to take estrogen plus progestin had a lower risk. Colorectal cancer, the second leading cause of death due to cancer in the United States, 1 has been the focus of several randomized trials of chemoprevention, 2 which have shown that calcium, 3 celecoxib, 4 aspirin, 5 and sulindac 6 , 7 inhibit the recurrence or development of colorectal polyps. The bile acid ursodiol was reported to reduce the incidence of colonic dysplasia or cancer in a prospective study of 52 patients with ulcerative colitis and primary sclerosing cholangitis. 8 Despite these advances, no evidence of a reduction in the risk of colorectal cancer has yet been provided for any intervention in a healthy population. 2 In observational studies, . . .