Endometrial cancer risk oral contraceptives

The occurrence of malignant tumors in patients taking oral contraceptives has been studied extensively. It is now clear that these compounds reduce the risk of endometrial and ovarian cancer. The lifetime risk of breast cancer in the population as a whole does not seem to be affected by oral contraceptive use. Some studies have shown an increased risk in younger women, and it is possible that tumors that develop in younger women become clinically apparent sooner. The relation of risk of cervical cancer to oral contraceptive use is still controversial. It should be noted that a number of recent studies associate the use of oral contraceptives by women who are infected with human papillomavirus with an increased risk of cervical cancer. 

Thus, our attention should shift from the concern of potential adverse effects to the health benefits imparted by hormonal contraceptives. The use of oral contraceptives for at least 12 months reduces the risk of developing endometrial cancer by 50%. Furthermore, the risk of epithelial ovarian cancer in users of oral contraceptives is reduced by 40% compared with that on nonusers. This kind of protection is already seen after as little as 3-6 months of use. Oral contraceptives also decrease the incidence of ovarian cysts and fibrocystic breast disease. They reduce menstrual blood loss and thus the incidence of iron-deficiency anemia. A decreased incidence of pelvic inflammatory disease and ectopic pregnancies has been reported as well as an ameliorating effect on the clinical course of endometriosis. 

Future efforts should be directed at optimizing current formulations to finally come up with an ideal oral contraceptive which would reduce the risk of breast, ovarian and endometrial cancer without any cardiovascular complications. 

The risk of endometrial cancer among women who have used oral contraceptives for at least 1 year is approximately 40% less than the risk in women who have never used oral contraceptives.9 There is additional evidence to suggest that the benefit of reduced risk for endometrial cancer is detectable within 1 year of use10-12 and that the benefit may persist for years following discontinuation of oral contraceptives.9... 

Long-term use of hormone-replacement therapy and concurrent use of progestins appear to contribute to breast cancer risk.7 The use of postmenopausal estrogen-replacement therapy in women with a history of breast cancer generally is considered contraindicated. However, most experts believe that the safety and benefits of low-dose oral contraceptives currently outweigh the potential risks and that changes in the prescribing practice for the use of oral contraceptives are not warranted. Oral contraceptives are known to reduce the risk of ovarian cancer by about 40% and the risk of endometrial cancer by about 60%. 

It has become apparent that reduction in the dose of the constituents of oral contraceptives has markedly reduced mild and severe adverse effects, providing a relatively safe and convenient method of contraception for many young women. Treatment with oral contraceptives has also been shown to be associated with many benefits unrelated to contraception. These include a reduced risk of ovarian cysts, ovarian and endometrial cancer, and benign breast disease. There is a lower incidence of ectopic pregnancy. Iron deficiency and rheumatoid arthritis are less common, and premenstrual symptoms, dysmenorrhea, endometriosis, acne, and hirsutism may be ameliorated with their use. 

A further follow-up and analysis of 3879 women, taken from two earlier US studies, who had been exposed to diethylstilbestrol during pregnancy has been presented (42). The results showed a modest association between diethylstilbestrol exposure and the risk of breast cancer (RR = 1.27 95% Cl = 1.07,1.52). The increased risk was not further aggravated by a family history of breast cancer, by use of oral contraceptives, or by HRT. There was no evidence that diethylstilbestrol was associated with a raised risk of ovarian, endometrial, or other hormone-associated cancers. 

The overall incidence of reproductive cancers attributable to oral contraceptive use has been estimated in a modeling analysis (72). The authors assumed a 50% reduction in ovarian and endometrial cancers associated with 5 years or more of tablet use, and used two alternative scenarios for breast and cervical cancer effects. If oral contraceptive use produces a 20% increase in breast cancer before age 50 and the same increase in cervical cancer, then for every 100 000 tablet users there would be 44 fewer reproductive cancers and these users would gain one more day free of cancer. If instead the increase in risk of early breast cancer and of cervical cancer is 50%, oral contraceptive users would have 11 fewer cancer-free days. 

Suggestive case histories raised at an early phase the notion of a possible correlation of oral contraceptives with endometrial cancer. Among cases of endometrial cancer there seemed to be an excess of users of oral contraceptives, particularly of the early high-dose estrogen type. With the virtual demise of these early products, the situation seems to have reversed a 1983 study from the Centers for Disease Control (CDC) in Atlanta showed that women who had used fixed combinations for oral contraception at some time in their lives had a relative risk of endometrial cancer of only 0.5 compared with never-users (112). The protective effect occurred only in women who had used oral contraception for at least 12 months, and lasted for at least 10 years after withdrawal. The WHO adopted the same view in 1988 in the light of multinational data (113). As in the case of hormonal replacement therapy, the protective effect seems to be due to the progestogen component. 

Many studies have also shown a duration-related protective effect of combined oral contraceptives on endometrial cancer, the risk before age 60 being reduced by 38% after 2 years of use and up to a 70% reduction after 12 years (114). This beneficial effect continued for at least 15 years after the end of use. As with ovarian cancer, the CASH study results suggest that the lower-dose combined oral contraceptives have a protective effect similar to that of the higher-dose tablets (115). 

The Centers for Disease Control Cancer and Steroid Hormone Study. Oral contraceptive use and the risk of endometrial cancer. JAMA 1983 249(12) 1600-4. 

Tumor-inducing effects are discussed in the monograph on estrogens. The risks of epithelial ovarian and endometrial cancer are reduced by combined oral contraceptives. Effects on other cancers are slight. 

The occurrence of malignant tumors in patients taking oral contraceptives has been studied extensively. It is now clear that these compounds reduce the risk of endometrial and ovarian cancer. The lifetime risk of breast cancer in the population as a whole does not seem to be affected by oral... 

The current consensus is that the contemporary low-dose preparations pose minimal risks in women who have no predisposing risk factors and, in fact, may provide certain beneficial health effects (e.g., protection against endometrial and ovarian cancer). Oral contraceptive pills have been associated with increased risk for myocardial infarction, stroke, and venous thromboembolism. However, studies have been published that suggest that these risks are minimal in appropriately chosen low-risk women. 

C. attenuate the increased risk of endometrial cancer associated with estrogen-only oral contraceptive agents. 

The health benefits of oral contraceptives go beyond contraception and outlast the reproductive years.41 These include reduced incidence of ovarian and endometrial cancers. Oral contraceptives do not increase the risk of breast cancer, heart disease, or blood clots.42... 

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