An association between polycystic ovary syndrome (PCOS)and endometrial carcinoma was first suggested in 1949, 14 years after the original description of the syndrome. Since then several studies have been published that seem to support this association. The prescription of hormonal treatment to reduce the risk of this complication is supported by the Guidelines for Good Clinical Practice of the Royal College of Obstetricians and Gynaecologists, UK, the Health Information website of the National Library of Medicine, USA, and in textbooks of gynaecological oncology.
A recent practice bulletin from the American College of Obstetricians and Gynecologists on the clinical management of PCOS (Obstet Gynecol 2002; 100: 1389-402) says that there is still no consensus on the "optimal progestin, duration and frequency of treatment to prevent endometrial cancer in women with PCOS". Chronic anovulation, obesity, and hyperinsulinaemia are all associated with PCOS as well as with endometrial carcinoma. It has been assumed that PCOS predisposes to endometrial cancer. However, the evidence for such an association is inconclusive. Although PCOS is associated with risk factors for endometrial cancer, it does not necessarily follow that the incidence or mortality from endometrial cancer is increased.
Large-scale studies of morbidity and mortality in unselected populations of women with PCOS are needed. Women with PCOS are increasingly aware of the possible risks, and it will be necessary to identify which of them, if any, are at increased risk and how this risk can be effectively reduced.