Hormonal contraception and risk of cancer.

BACKGROUND Fear from increased cancer risk is one of the most significant reasons for low acceptance of reliable contraceptive methods and low compliance. METHODS In this review, we included all cohort and case-control studies published in English up to December 2008. They were identified through a search of the literature using Pubmed and EMBASE. RESULTS Data about breast cancer risk indicate a slightly increased risk among current users of oral contraceptives (OC), an effect which disappears 5-10 years after stopping. Combined OC have a significant protective effect on the risk of ovarian cancer, and the protection increases with duration of use (relative risk decreased by 20% for each 5 years of use). The significant risk reduction has been confirmed for BRCA 1 and 2 mutation carriers. The risk of endometrial cancer is reduced by about 50% in ever users, a benefit which is greater with increasing duration of use. An association has been found between increased risk of cervical cancer and long-term OC use. Current OC use has been associated with an excess risk of benign liver tumours and a modest increased risk of liver cancer. None of large prospective cohort studies with prolonged follow-up has observed an increased overall risk of cancer incidence or mortality among ever users of OC, indeed several have suggested important long-term benefits. Specifically, protective effect of OC can be used as chemoprevention in young women who are BRCA mutation carriers. CONCLUSIONS Women wishing to use combined OC can be reassured that their decision is unlikely to place them at higher risk of developing cancer.