Phytoestrogen supplementation and endometrial cancer

Phytoestrogens are increasingly used by patients as "natural" alternatives to hormone replacement. Attention in scientific and lay literature has focused on their potential to prevent menopausal symptoms, bone loss, heart disease, or breast cancer. Less is known about effects on the endometrium, specifically, whether prolonged exposure to phytoestrogens could promote hyperplasia or neoplasia, as does unopposed estrogen.

We report the case of a woman diagnosed with grade 1 endometrioid adenocarcinoma of the endometrium whose history was notable for extensive use of supplemental phytoestrogens.

The effects of phytoestrogens on endometrial tissue are not known. Given their increasing popularity and availability in concentrated form as dietary supplements, additional research is warranted before we can counsel our patients regarding the safety of such supplements.