Two days ago, the US Federal Government published its biennial ‘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 bring the total of substances in the report, ‘known’ or ‘reasonably anticipated’ to pose a cancer risk, to 228.
The tenth edition of the report was forwarded to the US Congress and released by the US Department of Health and Human Services (HHS). It was prepared by the National Toxicology Program, an arm of the HHS located at the National Institute of Environmental Health Sciences, one of the US’ National Institutes of Health. The reports are published after lengthy study and scientific reviews by three successive expert panels of government and non-government scientists.
The report newly lists the group of hormones known as steroidal estrogens as ‘known human carcinogens.’ A number of the individual steroidal estrogens were already listed as ‘reasonably anticipated carcinogens’ in past editions, but this is the first report to so list all these hormones, as a group. As with all the other medications listed, the Report on Carcinogens does not address or attempt to balance potential benefits of use of these products.
Also newly listed as ‘known’ causes of cancer in humans are broad spectrum ultraviolet radiation, whether generated by the sun or by artificial sources, wood dust created in cutting and shaping wood, nickel compounds and beryllium and its compounds commonly used in industry. Beryllium and beryllium compounds are not new to the list but was previously listed as ‘reasonably anticipated to be a human carcinogen.’
The report is mandated by Congress as a way for the US 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 concerning these listings in an attempt to address how exposures have been reduced.
The report makes a distinction 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.
The report does not, however, assess the magnitude of the carcinogenic risk, nor does it address any potential benefits of listed substances such as certain pharmaceuticals. Listing in the report does not establish that such substance presents a risk to persons in their daily lives. Such formal risk assessments are the responsibility of US Federal, State, and local health regulatory agencies.
Newly listed as known human carcinogens are:
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, 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.
<b>Broad Spectrum Ultraviolet Radiation (UVR):</B>
UVR is produced by the sun as part of solar radiation and by artificial sources such as sun lamps and tanning beds, in medical diagnosis and treatment procedures, and in industry for promoting polymerisation reactions. The report cites data indicating a cause-and-effect relationship between this radiation and skin cancer, cancer of the lip and melanoma of the eye. The report goes on to say that skin cancers are observed with increasing duration of exposure and for those who experience sunburn. The individual components of UVR, which includes ultraviolet A, ultraviolet B and ultraviolet C radiation, are listed in the report, not as ‘known’, but as ‘reasonably anticipated’ human carcinogens.
Listed as a ‘known human carcinogen’ in this report, wood dust is created when machines and tools cut, shape and finish wood. Wood dust is particularly prevalent in sawmills, furniture manufacture and cabinet making. According to the report, unprotected workers have a higher risk of cancers of the nasal cavities and sinuses.
Used in many industrial applications as catalysts and in batteries, pigments and ceramics, the report newly lists nickel compounds as ‘known’ human carcinogens based on studies of workers showing excess deaths from lung and nasal cancers and on their mechanisms of action.