Benzene and lymphohematopoietic malignancies in humans

Background Quantitative evaluations of benzene-associated risk for cancer h ave relied primarily on findings from a cohort study of highly exposed U.S. rubber workers. An epidemiologic investigation in China (NCI/CAPM study) e xtended quantitative evaluations of cancer risk to a broader range of benze ne exposures, particularly at lower levels. Methods We review the evidence implicating benzene in the etiology of hemat opoietic disorders, clarify methodologic aspects of the NCI/CAPM study, and examine the study in the context of the broader literature on health effec ts associated with occupational benzene exposure. Results Quantitative relationships for cancer risk from China and the U.S. show a relatively smooth increase in risk for acute myeloid leukemia and re lated conditions over a broad dose range of benzene exposure (below 200 ppm -years mostly from the China study and above 200 ppm-years mostly from the U.S. study). Conclusions Risks of acute myeloid leukemia and other malignant and nonmali gnant hematopoietic disorders associated with benzene exposure in China are consistent with other information about benzene exposure, hematotoxicity, and cancer risk, extending evidence for hematopoietic cancer risks to level s substantially lower than had previously been established. Published 2001 Wiley-Liss, Inc.