What is the relationship between polycystic ovary syndrome and cancer?

Polycystic ovary syndrome (PCOS) is a term used to describe a collection of symptoms associated with not ovulating (producing an egg) on a monthly basis. It is associated with an imbalance in hormone levels. Women with PCOS might have an increased risk of endometrial (uterine) cancer. But PCOS does appear to increase the risk of breast or ovarian cancer.