Hormone replacement therapy and colorectal adenoma recurrence among women in the polyp prevention trial

Background: Epidemiologic studies have suggested that estrogen may protect against the development of colorectal cancers and adenomatous polyps. We co nducted a prospective study to evaluate the association between hormone rep lacement therapy (HRT) and adenoma recurrence among perimenopausal and post menopausal women participating in the Polyp Prevention Trial, a randomized dietary intervention study of individuals with colorectal adenomas. Methods : We used a questionnaire and interviews to collect detailed information, a t baseline and at each of four annual study visits, from 620 women regardin g hormone use, menopausal status, diet, alcohol consumption, and other risk factors. Adenoma recurrence was ascertained by complete colonoscopy at bas eline and after 1 and 4 years. Logistic regression models were used to eval uate the association between hormone use and adenoma recurrence after adjus ting for intervention group and for age and body mass index at baseline. Al l statistical tests were two-sided. Results: Adenomas recurred in 200 women . There was no overall association between adenoma recurrence and either ov erall hormone use (odds ratio [OR] = 1.01; 95% confidence interval [CI] = 0 .70 to 1.45), combined estrogen and progestin use (OR = 0.94; 95% CI = 0.57 to 1.56), or unopposed estrogen use (OR = 1.04; 95% CI = 0.68 to 1.59). HR T use was associated with a reduction in risk for recurrence of distal aden omas (OR = 0.56; 95% CI = 0.32 to 1.00) and a statistically nonsignificant increase in risk for recurrence of proximal adenomas (OR = 1.39; 95% CI = 0 .85 to 2.26). We observed a statistically significant interaction between t he HRT-adenoma recurrence association and age (P = .02). HRT was associated with a 40% reduced risk of adenoma recurrence among women older than 62 ye ars (OR = 0.58; 95% CI = 0.35 to 0.97) but with an increased risk among wom en younger than 62 years (OR = 1.99; 95 % CI = 1.11 to 3.55). Conclusions: HRT was not associated with a reduced risk for overall adenoma recurrence i n this trial cohort, although there was a suggestion of an age interaction. The effect of age on the association needs to be confirmed in other adenom a recurrence trials.