Breast cancer oral contraceptives

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... 

Meg estrolAceta.te. This compound is used outside the United States as an oral contraceptive. In the United States, it is used for the paUiative treatment of breast cancer and endometrial cancer, or as an adjunct to other therapies. Its use has been associated with an increased appetite and food intake and has been evaluated in the treatment of anorexia and cachexia (107). 

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. 

Marchbanks PA, McDonald JA, Wilson HG et al (2002) Oral contraceptives and the risk of breast cancer. N Engl JMed 346 2025-2032... 

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%. 

Jick H, Walker AM, Watkins RN, et al. Oral contraceptives and breast cancer. Am J Epidemiol 1980 112 577. 

Ethinyloestradiol Synthetic oestrogen Used for oestrogen replacement therapy in deficient states, both pre- and postmenopausal. Treatment of prostate cancer (male), breast cancer (post-menopausal women). Component of many oral contraceptives... 

The chief therapeutic uses of estrogens and progestins are as oral contraceptives and hormone replacement therapy. Progestins and SERMs are also important agents in the treatment of osteoporosis, breast cancer, endometrial cancer, and infertility. 

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. 

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. 

It is clear from the studies reported in Table 1 (133-149) that there is no simple relation between treatment with hormonal oral contraceptives and the incidence of breast cancer. As in the case of other neoplasms, studies are confounded by the influence of many factors, including age, parity, age at first delivery, family history, pre-existent fibrocystic disease, geographical or... 

Review of nine major studies of oral contraceptives Reduced risk of breast cancer in eight studies greater effect with higher doses clinically significant with 2 years of use (133)... 

Case-control study Link between oral contraceptives and breast cancer, but only in those aged 30-34 years coincidental (134)... 

Case-control study Significantly more cases of breast cancer with depot medroxyprogesterone no link with oral contraceptives (149)... 

There are some circumstances in which it is prudent to avoid using oral contraceptives, or in which frequent control of the state of the breasts is essential. These include (a) very long-term use before the first full pregnancy (b) prolonged use of high-dose formulations (c) uninterrupted use in women with a family history of breast cancer or with a personal history of fibroadenoma. 

Pike MC, Henderson BE, Casagrande JT, Rosario I, Gray GE. Oral contraceptive use and early abortion as risk factors for breast cancer in young women. Br J Cancer 1981 43(l) 72-6. 

Vessey MP, McPherson K, Doll R. Breast cancer and oral contraceptives findings in Oxford-Family Planning Association contraceptive study. BMJ (Clin Res Ed) 1981 282(6282) 2093-4. 

Ory GW, Layde OM, et al. Long term oral contraceptive use and the risk of breast cancer. Paper presented at 31st Annual Epidemic Service ConferenceAtlanta, Georgia . 1982. 

---