Endometrial cancer and HRT

Abstract

Inappropriate use of hormone replacement therapy (HRT) may increase the risk of endometrial cancer. Unopposed oestrogen is associated with the development of endometrial hyperplasia and if continued of endometrial cancer. The addition of progestogen for at least 12 days in each cycle will prevent hyperplasia in the short term but with use over 5 years there will still be an increased risk of endometrial disease. Long cycle therapy with a progestogen course every three months or more will reduce the frequency of bleeding, which will be popular, but protection of the endometrium is less certain.

The addition of continuous progestogen to oestrogen has the merit of correcting endometrial hyperplasia without atypia to normal and in the long-term will keep the endometrium atrophic. There is no increase in the risk of endometrial cancer with such continuous combined regimens and possibly even a reduced risk.

The progestogen in HRT is only required for endometrial protection, so it is logical to give the hormone direct to the endometrial cavity. The Mirena^® intrauterine system that releases levonorgestrel has been available for many years as a contraceptive and treatment for menorrhagia, and recently also for the progestogen component of combined HRT regimens. A smaller experimental device designed for the postmenopausal uterus is being investigated and may become a suitable option in the future.

For women who have had complete removal of a stage 1 endometrial cancer, there is no evidence that subsequent HRT will increase the risk of further disease.