A Cohort Study on Trichloroethylene Exposure and Cancer Mortality

Abstract

The recent report from the National Cancer Institute on trichloroethylene [an industrial chemical of occupational significance] causing hepatocellular carcinomas in mice has called for an epidemiologic evaluation of possible cancer effects in man. The present, fairly small cohort study comprising 518 men with rather low levels of exposure as estimated through trichloroacetic acid in the urine, did not reveal any excess cancer mortality. Thus, requiring 10 yr of latency time, the subcohort with trichloroacetic acid in urine above 100 mg/l (i.e., exposure supposed to be above 30 ppm) showed a close agreement between expected and observed number of cancer cases as did the subcohort with lower exposure (548 and 3643 person-years of observation, respectively). The cancer risk to man from trichloroethylene can by no means by ruled out from this study, particularly with regard to uncommon malignancies such as liver cancer. Nevertheless there is probably no serious cancer hazard at low exposures.