10th Report on Carcinogens, Selected Text From Press Release, Dec. 11, 2002
In 2002, the federal government published the 10th Report on Carcinogens, adding steroidal estrogens used in estrogen replacement therapy and oral contraceptives to its official list of “known” human carcinogens. This and 15 other new listings brought the total of substances in the report, “known” or “reasonably anticipated” to pose a cancer risk, to 228.
The Report on Carcinogens is mandated by Congress as a way for the government to help keep the public informed about substances or exposure circumstances that are “known” or are “reasonably anticipated” to cause human cancers.
The report also identifies current regulations that are attempting to reduce exposures.
Each report (we are now awaiting nominations for the 12th Report on Carcinogens) distinguishes between “known” human carcinogens, where there is sufficient evidence from human studies, and “reasonably anticipated” human carcinogens, where there is either limited evidence of carcinogenicity from human studies and/or sufficient evidence of carcinogenicity from experimental animal studies.
Steroidal estrogens.These are a group of related hormones that control sex and growth characteristics and are commonly used in estrogen replacement therapy to treat symptoms of menopause, and in oral contraceptives. The report cites data from human epidemiology studies that show an association between estrogen replacement therapy and a consistent increase in the risk of endometrial cancer (cancer of the endometrial lining of the uterus) and a less consistent increase in the risk of breast cancer.
As for the other common use for steroidal estrogens (oral contraceptives), the report says the evidence suggests estrogen-containing oral contraceptives may be associated with an increased risk of breast cancer but may protect against ovarian and endometrial cancers.