Risk of cancer development in relation to oral contraception.

Combined oral contraceptives (COCs) are among the most widely used effective and reversible means of family planning. Their beneficial effects are well documented, but many questions are still raised concerning a possible association between the use of COCs and the development of cancer. The authors provide a broad and up-to-date review of the literature regarding the relation between COC use and carcinogenesis in different organs. Studies have not unequivocally confirmed that such a relation exists with regard to breast cancer. Much research focused on the influence COC use could have on the incidence of cervical cancer; most of it was analyzed by J. Smith and co-workers. These authors confirmed the existence of a weak relation between COC use and the development of cervical carcinoma, especially in women using COCs for longer periods. Ovarian carcinoma has the worst prognosis of all cancers of reproductive organs in women. The risk of developing ovarian cancer in women using COCs is at least 40% smaller than in other women; the degree of protection given by COCs is directly proportional to the duration of use of this form of contraception. Reliable scientific data prove convincingly that the risk of endometrial cancer is smaller in women who used COCs than in women who never took them.