Research indicates that polycystic ovary syndrome can increase the risk of a woman developing ovarian cancer. However, scientists have yet to confirm this link in large population studies as of 2015, says the National Institutes of Health, an agency of the United States Department of Health and Human Services.
Studies also show that polycystic ovary syndrome triples the risk of endometrial cancer in women, reports the National Institutes of Health. Irregular periods or a lack of periods can result in the thickening of the endometrium, which can, in turn, lead to endometrial cancer. Moreover, some small studies suggest an elevated risk of breast cancer in women with polycystic ovary syndrome.