Long-term use of progestogens: Colon adenoma and colon carcinoma

Abstract

Colon cancer is the second most common cancer in women in the Western world and there is a trend towards an increasing risk. Colon adenoma is a potential precursor for colon cancer. Adenoma and carcinoma of the colon seem to be influenced by estrogens and progesterone/progestins. This is related to the presence of estrogen and progesterone receptors, with apparently higher concentrations in colon cancers than in adenomas. Epidemiological data and the finding of a significant reduction in colon cancer risk related to hormone replacement therapy (HRT), and in particular the length of HRT intake, indicate that progesterone/progestins have a preventive effect. This has not been shown with postmenopausal estrogen replacement therapy (ERT) alone. Furthermore, the recurrence rate of adenoma appears to be reduced, and the survival of colon cancer patients improved, with HRT; such effects have not been documented with ERT.