Cancer and PCOS.

It has been known that patients with PCOS are at increased risk for Endometrial cancer for many years. The unopposed estrogen (i.e. lack of ovulation and subsequent menses) is thought to continuously stimulate the uterine lining eventually leading to cancer. It is thought that endometrial cancer may progress from benign hyperplasia to atypical hyperplasia (pre-cancer) to frank endometrial cancer. Most patients with endometrial cancer are older than 40. The risk factors the have include obesity, hypertension, anovulation, nulliparity. In a study of patients less than the age of 40, 25 % were found to have PCOS. Insulin stimulates the endometrium to produce estrogen, acts as a mitogen, and stimulates growth factors (i.e. Insulin-like growth factor) that may help endometrial cancer develop and progress.

One study examined the prevalence of benign breast disease in a cross section of patients with PCOS and found that there were no differences compared to the healthy age-matched control population in the following: fibrocystic disease, lump thickening, hyperplasia, calcifications, fibroadenomas, pain, or breast discharge. In another study, breast cancer was found to be decreased 50 % in a study of over 4700 women. Additionally, a 31-year follow-up study from the UK of patients with PCOS did not find an increase in breast cancer. More studies are needed to confirm these findings, but they seem reassuring.

Ovarian cancer was found to be 2-3 fold increased in PCOS patients, and this was greatest in non-obese women without prior birth control pill use. Obviously, we are learning more about these risks and the causal relationships have yet to be determined.

It may be worthwhile to increase surveillance by using pelvic ultrasound exams to assess the ovaries and endometrium and biopsy the abnormally thick endometrium as indicated for the clinical presentation. Additionally, we should still follow the current guidelines for mammography.