Cigarette Smoke : Cancer Risk at Low Doses
The regulation of exposure to low-dose carcinogens is beset with difficulties and uncertainties. Ethical considerations rule out the use of human experiments to determine risk from low dose carcinogens. Even if animal experiments are used, a number of animals would be required to test for carcinogens at low doses. Nevertheless, safe levels of human exposure must be set. Thus, methods based on extrapolation from animal experiments with a relatively small number of animals exposed to high dosages of potential carcinogens are being adopted as the basis for regulating human exposure to low dosages of carcinogens . Since it has been impossible to determine a dosage level at which there is no cancer hazard, an alternate “virtually safe” dose method has become common. The virtually safe dose is a dose at which the cancer risk is no greater than some very small risk, say, a one-in 105, 106, or 108 chance of developing cancer in a lifetime. For example, an action level of 100 μg/liter for total trihalomethanes in drinking water has been proposed by the EPA as prudent for these animal carcinogens : the risk of cancer resulting from low-dose x-ray exposure has been determined in this way and used to establish acceptable x-ray dosage levels for mammography screening .
Key WordsVirtually safe dose environmental carcinogens smoking and health low dose carcinogens
Unable to display preview. Download preview PDF.
- 1.National Research Council, Drinking Water and Health, Washington: National Academy of Sciences (1977).Google Scholar
- 2.The Federal Register, Interim primary drinking water regulations, Part II EPA: 5756–5780 (February 9, 1978).Google Scholar
- 3.Bailar, J. C., Mammography : A contrary view, Annals of Internal Medicine, 84:77–84 (1976).Google Scholar
- 5.Hammond, E. C., and Horn, P., Smoking and death rates — report on 44 months of follow-up of 187,783 men - 1. Total Mortality, Journal of Amer. Med. Assoc., 166(10) : 1159–1172 (1978).Google Scholar
- 6.Dorn, H. D., Tobacco consumption and mortality from cancer and other diseases, Public Health Reports, 74:581–593 (1959).Google Scholar
- 7.Kahn, H. A., The Dorn study of smoking and mortality among U.S. veterans; report on 8½. years of observation, in: Epidemiological approaches to the study of cancer and other chronic diseases, W. Haenszel, ed., National Cancer Institute Monograph 19, U.S. Department of Health, Education, and Welfare, Public Health Service, National Cancer Institute, 1 (1966).Google Scholar
- 8.Mantel, N., An improved Mantel-Bryan procedure for “safety testing” of carcinogens, Cancer Research, 35:865–872 (1975).Google Scholar
- 9.Guess, H. A., and Crump, K. S., Low-dose-rate extrapolation of data from animal carcinogenicity experiments — analysis of a new statistical technique, Math. Biosciences, 32 (1976).Google Scholar
- 13.Guess, H., Crump, and Peto, R., Uncertainty estimates for low-dose-rate extrapolations of animal carcinogenicity data, Cancer Research, 37:3475–3483 (1977).Google Scholar
- 14.Hammond, E. C., Garfinkel, L., Seidman, et al., Some recent findings concerning cigarette smoking, in: Origins of Human Cancer, H. J. Hiat, J. D. Watson, and J. A. Winsten, eds., Cold Spring Harbor, New York, Cold Spring Laboratory (1977).Google Scholar
- 16.The Health Consequences of Smoking, U.S. Department of Health, Education, and Welfare, Public Health Service, Center for Disease Control, Atlanta, Georgia (1975).Google Scholar