NEW ORLEANS, Mar 27 (Reuters Health) - Although estrogen has been shown to protect against the formation of polyps in the colon, National Cancer Institute (NCI) researchers said Tuesday that relatively young women who take hormone replacement therapy (HRT) may be at risk for developing new polyps after they have already had some removed.

On the other hand, older women--those over age 62--appear to be less likely to develop new polyps if they are taking HRT.

Cancerous changes can take place in polyps, so they are often removed to reduce the risk of colon cancer.

The findings were presented by NCI scientist Karen Woodson at the American Association for Cancer Research meeting here.

Woodson said it is not clear why the younger women in the study--those under age 62--had an increased risk of recurrence. The NCI conducted the Polyp Prevention Trial in nearly 2,000 men and women to assess whether diet, alcohol, and lifestyle modifications would help prevent new polyp formation in people who already had polyps removed.

Participants were given a full colonoscopy--an examination of the entire colon with a lighted instrument--at the beginning of the study, and again at 1 year and 4 years.

Woodson took a closer look at women approaching or just past menopause in the study. These 620 women ranged in age from 36 to 86. Of these women, 33% had a recurrent polyp and 40% said they were taking either estrogen alone or some combination of estrogen and progestin to combat menopausal side effects.

Overall, when the researchers looked at women of all ages, there appeared to be no association between polyp recurrence and hormone use, no matter which type of HRT was taken. However, the researchers looked at women over age 62 taking HRT, and those younger than 62. In that group, there was a 70% increase in risk of a polyp recurrence. Conversely, the older women had a 30% reduction in risk.

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• Colonic Diseases (General)
• Menopause