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BULLETIN OF THE WORLD HEALTH ORGANIZATION. 1993; 71(6):669-76.Depot-medroxyprogesterone acetate (DMPA) is a highly effective long-acting progestational contraceptive, which is administered by injection. DMPA has been widely used in Thailand and New Zealand. The licensing, acceptability, and prevalence of use have been influenced by concern that DMPA may increase the risk of cancer, in particular cancer of the breast. The results of toxicological tests in animals and epidemiological studies in humans concerning the carcinogenicity of DMPA are reviewed. Animals injected with DMPA were exposed to far greater concentrations of the progestogen than were animals tested with orally administered 19-nortestosterone derivatives. In beagle dogs, a unique response to DMPA led to increased serum growth hormone, which was probably responsible for the tumorigenic effect of DMPA on the mammary gland. However, women taking contraceptive doses of DMPA have no significant elevation of serum growth hormone. Available toxicological data do not seem to indicate that DMPA is different from other progestogens in its tumorigenic potential. Epidemiological studies reassure that use of DMPA does not increase breast cancer risk overall. Elevated risks in the same or similar subgroups were observed in the WHO and New Zealand studies, consistent with an acceleration in detection of pre-existing cancer. The data were not compatible with DMPA as an initiating agent. Research is needed on the biological mechanisms of action of progestogens on the human breast. Findings from studies of DMPA and invasive cervical cancer showed no overall increase in risk of cervical cancer and no association between DMPA and cervical cancer. Data from the WHO study provided evidence that DMPA protects against endometrial cancer and that DMPA use was not associated with either an increased or decreased risk of ovarian cancer. Therefore, restriction of DMPA use as contraceptive on the grounds of risk of neoplasia is not recommended.
CONTRACEPTION. 1994 Mar; 49(3):185-8.Depot-medroxyprogesterone acetate (DMPA) is currently used for contraception by about nine million women in more than 90 countries. DMPA injected intramuscularly at a dose of 150 mg every 3 months, is among the most effective reversible contraceptive methods. The reluctance of the US Food and Drug Administration (FDA) to approve DMPA in 1992 was attributed to the occurrence of mammary neoplasia in beagle dogs and of endometrial cancer in two of sixteen rhesus monkeys after long-term DMPA treatment. The beagle dog responds to DMPA with a release of growth hormone which is probably the cause of the tumorigenic effect of DMPA on the mammary gland. Around 1990 findings were published from a WHO multicenter study in Kenya, Mexico and Thailand and studies from Costa Rica and New Zealand. In 1993, a WHO meeting of experts reviewed the available data on use of DMPA and cancer risk in women as well as recent toxicology data. DMPA exerts a protective effect against endometrial cancer. The epidemiological studies report no association between the risk of ovarian cancer and the use of DMPA. There was a lack of an association between cervical cancer and DMPA. Two well-designed epidemiological studies did not provide evidence for an increase in overall risk of breast cancer among women having used DMPA. However, both studies reported a weak association between current and recent use of DMPA and breast cancer although there was no evidence of increased risk for women who had stopped using DMPA several years ago. Women who were less than 35 years old at diagnosis, an age at which breast cancer is rare, also showed a slightly increased risk. DMPA can cause an irregular bleeding pattern, it is not immediately irreversible, and there is a relatively slow return of fertility after discontinuation. Yet for women who wish for medium- or long-term contraception, DMPA is one of the alternatives to be considered.
In: McDaniel EB, ed. Second Asian Regional Workshop on Injectable Contraceptives. Oklahoma City, Oklahoma, World Neighbors, 1982. 39-44.The best available data on the possible side effects of Depot Medroxyprogesterone Acetate (DMPA) are examined so that physicians and health officials can decide for themselves whether DMPA is appropriate for use in their countries. Several evaluations of the scientific evidence on the safety of DMPA have taken place in the last few years. The US Food and Drug Administration (FDA) announced in 1978 that it would not approve DMPA for use in the US. Subsequently, the World Health Organization's (WHO) Toxicology Review Panel conducted a review and found no reason to recommend that DMPA be withdrawn from use. In 1980 an Ad Hoc Consultative Panel presented its findings and recommendations to the US Agency for International Development (USAID). The Panel recommended that USAID make DMPA available to national family planning programs upon request. This recommendation was based on careful consideration of the medical and ethical issues involved by Panel members with expertise in the fields of obstetrics and gynecology, animal physiology and toxicology, epidemiology, pathology, law, and health policy. DMPA is currently approved for contraceptive use in more than 80 developed and developing countries. Each of the 6 reasons for FDA's denial of approval of DMPA are reviewed: studies using beagle dogs showed an increased incidence of mammary tumors associated with DMPA use; the availability of a number of alternative methods of contraception in the US and the lack of clear evidence that a significant patient population in need of DMPA exists in the US; the possibility that bleeding disturbances caused by the drug may lead to the administration of estrogen, thus decreasing the benefits of a progestogen only contraceptive; the possibility that exposure of fetuses to DMPA, if pregnancy occurs, poses a risk of congenital malformation; and reservations about the ability of the post marketing study for breast and cervical carcinoma. As a result of species differences in reactions to DMPA, the WHO Toxicology Review Panel, the Ad Hoc Panel, and the UK Commission on Safety of Medicines have stated that it is not possible to conclude from the beagle studies that DMPA poses any increased risk of breast cancer to women. The Ad Hoc Panel found little information on the effects of progestogen alone and concluded that the data fail to suggest that DMPA poses more of a threat of fetal malformation than do other hormonal contraceptives. Thorough discussion of menstrual changes with prospective DMPA users and supportive patient counseling are the best methods of dealing with concerns about irregular bleeding and amenorrhea. Regarding endometrial cancer, preliminary evidence suggests that progestogens may even protect against endometrial cancer.