Long term use of hormone replacement therapy does not increase the risk of endometrial cancer and may even prevent it.

In the largest long-term study of its kind, researchers at the University of Sheffield in the UK have investigated the effect of hormone replacement therapy on the endometrium (lining of the womb). A group of 534 postmenopausal women took continuous combined hormone replacement (estrogen plus progestogen) for five years.

The researchers took biopsies of the endometrium before the study, after nine months, between 24 and 36 months, and finally at the end of the study. At the start, 21 women had endometrial abnormalities suggestive of early cancer, but the samples reverted to normal after nine months of hormone treatment. At the end of the study, there were no cases of endometrial cancer. This suggests, say the researchers, that continuous combined hormone replacement does not increase the risk of endometrial cancer - indeed it may even protect from the disease.

Source

British Medical Journal 3rd August 2002