Hormone replacement therapy that uses estrogen can reduce the side effects of breast cancer therapy without making the cancer come back more often. This is what researchers around Søren Cold from the Danish University Hospital Odense report in the “Journal of the National Cancer Institute”. Previous research had suggested that estrogen administration would increase the risk of tumor recurrence.
Some types of breast cancer have binding sites for the sex hormone estrogen on the surface of their cells. If the hormone binds to one of these receptors, it promotes tumor growth. Doctors therefore prescribe drugs that either stop the production of estrogen or prevent it from docking. However, the resulting lack of estrogen has unpleasant consequences for those treated, such as vaginal dryness, hot flashes or sleep disorders. The side effects can be alleviated either by taking the hormone as a vaginal ointment or by using menopausal hormone therapy (MHT). It helps women going through menopause to increase estrogen levels throughout the body.
The Danish research group analyzed the data of 8,461 sick women who were treated with anti-hormonal drugs after tumor surgery. 1957 of them were also prescribed vaginal estrogen therapy, 133 women were treated exclusively or additionally with MHT. After ten years, 15 percent of patients on vaginal estrogen therapy reported that the tumor had returned. In the MHT group, the recurrence rate was 17 percent. The researchers found no significant difference to women who did not use either treatment.