| Pentachlorophenol and Cancer Risk: Focusing the Lens on Specific Chlorophenols and Contaminants Glinda S. Cooper and Samantha Jones National Center for Environmental Assessment, U.S. Environmental Protection Agency, Washington, DC, USA Abstract
Objective: Pentachlorophenol, a fungicide widely used as a wood preservative, was classified in 1999 by the International Agency for Research on Cancer as a possible human carcinogen. We reviewed currently available data to determine the extent to which recent studies assist in distinguishing the effect of pentachlorophenol from that of its contaminants (e.g., dioxins and other chlorophenols) . Data sources and extraction: We performed a systematic review of published studies pertaining to cancer risk in relation to pentachlorophenol exposure, focusing on results pertaining specifically to all cancer sites and specific hematopoietic cancers, and data pertaining to risks associated with other types of chlorophenols, dioxins, or furans. Synthesis: The pentachlorophenol studies presented considerable evidence pertaining to hematopoietic cancers, with strong associations seen in multiple studies, in different locations, and using different designs. There is little evidence of an association between these cancers and chlorophenols that contain fewer than four chlorines. The extension of a large cohort study of sawmill workers, with follow-up to 1995, provided information about risks of relatively rare cancers (e.g., non-Hodgkin lymphoma, multiple myeloma) , using a validated exposure assessment procedure that distinguishes between exposures to pentachlorophenol and tetrachlorophenol. In contrast with dioxin, pentachlorophenol exposure has not been associated with total cancer incidence or mortality. Conclusions: The updated cohort study focusing on pentachlorophenol provides increased statistical power and precision, and demonstrates associations between hematopoietic cancer and pentachlorophenol exposure not observed in earlier evaluations of this cohort. Contaminant confounding is an unlikely explanation for the risks seen with pentachlorophenol exposure. Key words: cancer, childhood leukemia, chlorophenols, dioxins, furans, multiple myeloma, non-Hodgkin lymphoma, pentachlorophenol, soft-tissue sarcoma. Environ Health Perspect 116:1001–1008 (2008) . doi:10.1289/ehp.11081 available via http://dx.doi.org/ [Online 11 April 2008]
Address correspondence to G.S. Cooper, National Center for Environmental Assessment (8601-P) , U.S. Environmental Protection Agency, 1200 Pennsylvania Ave. NW, Washington, DC 20460 USA. Telephone: (703) 347-8636. Fax: (703) 347-8689. E-mail: cooper.glinda@epa.gov The views expressed are those of the authors and do not necessarily reflect the views or policies of the U.S. EPA. The authors declare they have no competing financial interests. Received 16 November 2007 ; accepted 10 April 2008.
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