Anovulation with or without PCO, hyperandrogenaemia and hyperinsulinaemia as promoters of endometrial and breast cancer.

The relationship of infertility, endocrinology and cancer has become clearer in recent years. Polycystic ovaries (PCO) increase the risk of endometrial cancer. Prolonged amenorrhoea, therefore, should be prevented in such cases with the use of cyclical progestogens, in order for regular withdrawal bleeds to be induced and the endometrium protected from long-term unopposed oestrogen stimulation. There is no secure evidence base on which a relationship between PCO and breast cancer can be based. No specific breast screening for women with PCO is, therefore, recommended. Hyperandrogenaemia and hyperinsulinaemia are conditions whose significance in terms of increasing both endometrial and breast cancer risks is increasingly recognised. The exact mechanism with which they influence carcinogenesis is still far from clear. Whether they act in isolation or as expressions of the common background of the metabolic syndrome - in interaction with other components of this syndrome - is still the subject of research.