Federal Government Adds Steroidal Estrogens to List of ‘Known Human Carcinogens’

The federal government yesterday added steroidal estrogens used in oral contraceptives and hormone replacement therapies to the list of "known human carcinogens," a move that "significantly upgrades" their risk, the Washington Post reports. Estrogen was added to the list, which is mandated by Congress and produced every two years, based on "a review of medical literature over the past two years," Christopher Portier, director of the Environmental Toxicology Program for the National Institute of Environmental Health Sciences, said, adding that the decision was not based on recent findings that hormone replacement therapy could increase a woman's risk of breast cancer and heart disease (Kaufman, Washington Post, 12/12). According to the "10th Report on Carcinogens," which was prepared by the NIEHS National Toxicology Program and released yesterday by HHS, "data from human epidemiology studies ... show an association between estrogen replacement therapy and a consistent increase in the risk of endometrial cancer ... and a less consistent increase in the risk of breast cancer" (NIH release, 12/11). Although steroidal estrogens were one of 15 new items to be added to the list of potential cancer causing agents, scientists said it is not known whether the risk of cancer remains when estrogens are used in combination with other hormones, as is common in oral contraceptives and hormone replacement therapy. In addition, Portier said the list does not "make any recommendations about whether and when estrogen products should be used," adding that women seeking to use oral contraceptives or hormone replacement therapy should consult their physician, according to the Post (Washington Post, 12/12).