Linking environmental cancer with occupational epidemiology research: the role of the International Agency for Research on Cancer (IARC).
BACKGROUND
The International Agency for Research on Cancer (IARC) provides the most credible assessment of carcinogenicity for the scientific community. IARC Monographs also suggest areas where new laboratory and epidemiology research on cancer should be focused.


METHODS
This presentation examines two recent IARC reports on silica and coal dust (from 1997), and on occupational exposures to insecticide and pesticide applications (from 1991).


RESULTS
From the Silica Monograph, the research implications suggest that laboratory and epidemiology studies would be useful focusing on mixtures of hazards where silica is a significant component of the respirable environment: in coal mining (which has an excess of gastric cancers) with variations in silica exposure; in uranium mining where there is silica dust plus radon decay products, in foundries and steel-making plants where silica exposure is common as are other carcinogenic hazards; in agriculture where dusty farming may be common, and comparisons are needed with other polymorphs of silica, including amorphous quartz. Additional studies of lymphatic, dermal, and gastrointestinal malignancies are needed to determine if the evidence of silicocarcinogenesis extends to these tumor sites. Finally, some fundamental studies of adsorptive capability of silica and resultant biologic activity, including biomarker studies, are needed. In the pesticide realm, there are many active ingredients that have been shown to be 2B (or possible) carcinogens based on animal studies (or other evidence). Industrial epidemiology studies of workers manufacturing or handling chemicals such as atrazine, chlordane, dichlorvos, 2,4-D, and DDT should be undertaken. Cancer epidemiology associations have been demonstrated for chemicals such as phenoxy acid herbicides, 2,4,5-T, lindane, methoxychlor, toxaphene, and several organophosphate insecticides for which laboratory studies are needed.


CONCLUSIONS
IARC reviews offer many leads for future research and insightful protocols that can provide new leads for studying these common exposures under novel environmental conditions.
Goldsmith
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The George Washington University School of Public Health, Washington, DC 20037, USA.
D000818:Animals; D003031:Coal / Q000633:toxicity; D004391:Dust / Q000009:adverse effects; D004781:Environmental Exposure / Q000009:adverse effects*; D006801:Humans; D007390:International Agencies; D009369:Neoplasms / Q000453:epidemiology* / Q000209:etiology; D009784:Occupational Diseases / Q000453:epidemiology* / Q000209:etiology; D016273:Occupational Exposure / Q000009:adverse effects*; D010575:Pesticides / Q000633:toxicity; D012822:Silicon Dioxide / Q000633:toxicity*
D003031:Coal; D004391:Dust; D010575:Pesticides; D012822:Silicon Dioxide