CANCER RISK DUE TO OCCUPATIONAL EXPOSURE TO POLYCYCLIC AROMATIC-HYDROCARBONS

Polycyclic aromatic hydrocarbons (PAHs) demonstrate carcinogenic activ ity in animal models. Although some epidemiologic studies have implica ted PAHs as risk factors for human cancer, the evidence reported to da te has not been consistent. The purpose of this report is to describe the associations between occupational exposure to PAHs in the workplac e and each of 14 types of cancer. A population-based, case-control stu dy was carried out in Montreal to investigate associations between a l arge variety of environmental and occupational exposures on the one ha nd, and several types of cancer on the other. A detailed job history w as obtained from each subject along with information on a number of po tential confounders. Each job history was reviewed by a team of expert s, who used this information to construct a corresponding history of o ccupational exposures. Among the PAH exposures considered were benzo(a )pyrene (B(a)P) and five categories of PAHs defined on the basis of th e source material, namely, wood, petroleum, coal, other sources, and a ny source. Altogether, 3,730 cancer patients and 533 population contro ls were interviewed and their job exposure histories coded. For each o f 14 types of cancer analyzed, three control groups were available: ot her cancer patients, population controls, and the pooled set of cancer and population controls. The associations between 14 cancer types and 6 PAH exposures were analyzed using logistic regression methods. For most types of cancer evaluated, there was no evidence of excess risk d ue to PAHs at the levels encountered in the occupations in which PAH e xposure has been prevalent in the Montreal area. For a few cancer site s-the esophagus, the pancreas, and the prostate gland-there were sugge stions of excess risk; these observations are noteworthy hypotheses fo r further investigation. For lung cancer, there appeared to be an incr eased risk due to PAHs among nonsmokers and light smokers, but not amo ng heavy smokers. (C) 1995 Wiley-Liss, Inc.