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.
Most patients with endometrial cancer are older than 40. The risk factors the have include obesity, hypertension, anovulation, nulli-parity.
In a study of patients less than the age of 40, 25 % were found to have PCOS.
Breast cancer was found to be decreased 50 % in a study of over 4700 women. More studies are needed to confirm these findings.
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.