A case-referent study of soft-tissue sarcoma and Hodgkin's disease. Farming and insecticide use

A population-based case-referent study in Kansas examined the relationship between exposure to insecticides and the development of soft-tissue sarcoma (STS) and Hodgkin's disease (HD). Data from telephone interviews for 133 STS cases, 121 HD cases, and 948 referents indicated that STS was associated with use of insecticides on animals, but not on crops. HD was not significantly associated with either use. STS risk was higher among the farmers who themselves mixed or applied insecticides to animals than among farmers who did not. Farmers who failed to use any protective equipment to reduce insecticide exposure were at a significantly elevated risk of STS. Risk rose with early calendar year of first use. The excess risk appeared to be primarily among fibrous and myomatous sarcomas with little association seen for lipomatous or other STS neoplasms. Myomatous sarcomas increased significantly with duration and time since first use of insecticides on animals. If the reported association between STS and insecticides is causal, the data suggest that exposure to the agent(s) responsible may have been reduced in the mid-1950s or the agent(s) have an average latency period for STS of at least 20 years.