A new study shows the risk of developing breast cancer may double for women taking the long-acting injectable birth control Depo-Provera ®.
The depo-medroxyprogesterone acetate (DMPA) injection, marketed as the brand name Depo-Provera and depo-subQ provera, is in a class of medications called progestins. It first received approval for use from the U.S. Food and Drug Administration (FDA) in 1992. Physicians prescribe this drug for pregnancy contraception and treatment of endometriosis. However, it contains the same progestin found by the Women’s Health Initiative clinical trial to increase risk of breast cancer in postmenopausal woman.
Researchers from the Fred Hutchinson Cancer Research Center conducted a population-based-control study of 919 women with no history of breast cancer and 1028 women diagnosed with invasive breast cancer between the ages of 20 and 44. Ten percent of women in the study reported using DMPA as a birth control method. They found that women who recently used DMPA for twelve months or longer had a 2.2-fold increased risk of invasive breast cancer. The breast cancer risk went away within months of discontinuation of the drug.
“Although breast cancer is rare among young women and the elevated risk of breast cancer associated with DMPA appears to dissipate after discontinuation of use, our findings emphasize the importance of identifying the potential risks associated with specific forms of contraceptives given the number of available alternatives,” study authors wrote.
The study adds to a growing body of published studies from around the world of DMPA and breast cancer risk, but this is the first study to evaluate associations between DMPA use and risk of different breast cancer subtypes.
Effect of depo-medroxyprogesterone acetate on breast cancer risk among women 20-44 years of age appears in the April 15 print issue of the journal Cancer Research. The National Cancer Institute and the Department of Defense Breast Cancer Research Program funded the study.
“In the United States many women have numerous options for contraception, and so it is important to balance their risks and benefits when making contraceptive choices,” said lead study author and breast cancer epidemiologist Christopher I. Li, M.D., Ph.D., of Fred Hutchinson Cancer Research Center in a press release.