I have PCOS and have been through all the fertility treatments just short of invitro. I was treated at Johns Hopkins which is supposed to be one of the best infertility treatment hospitals in the country.
PCOS can cause skin tags, extra facial hair, thinning head hair, heart disease, little or no periods and diabeties (sp?). It may also cause excess weight gain - usually around the tummy area and make it difficult to lose.
I have never heard of it causing ovarian cancer. However if you do not have regular periods that can cause endometrial cancer (lining of the uterus). One treatment is to take progestrone pills once a quarter to bring on the period.