Occupational trichloroethylene exposure and kidney cancer risk: a meta-analysis

Monday, October 24, 2011 — Poster Session I
Noon – 2:00 p.m.	Natcher Conference Center	NCI	CANCER-11

Authors

• S Karami
• Q Lan
• N Rothman
• PA Stewart
• LE Moore

Abstract

Inconsistent epidemiological findings, debate over interpretation, and extrapolation of findings from animal models to humans, have produced uncertainty surrounding the carcinogenicity of trichloroethylene (TCE), a “probable human carcinogen.” We updated meta-analyses of published studies exploring occupational TCE exposure and kidney cancer by incorporating results from a recent case-control study designed specifically to assess occupational TCE exposure. Applying stringent inclusion criteria, studies included those assessing chlorinated solvents, degreasers, or TCE exposures. Studies were classified as group I or II, by quality of study design and exposure assessment. Sensitivity analyses examined sources of heterogeneity. Case-control (n:13) summary estimates were elevated overall [OR=1.67(95%CI=1.25-2.23),p-heterogeneity=0.02] and for group I studies [OR=1.72(95%CI=1.23-2.40),p-heterogeneity=0.03]; removing heterogeneity by excluding an outlier study revealed similar associations and a significant estimate for group II studies [OR=2.16(95%CI=1.31-3.56),p-heterogeneity=0.56]. Cohort (n:17) summary estimates were marginally significant overall [RR=1.24(95%CI=0.98-1.57),p-heterogeneity<0.001] and for group I studies [RR=1.44(95%CI=0.99-2.12),p-heterogeneity=0.02]; excluding an outlier study revealed significant estimates for group I [OR=1.29(95%CI=1.04-1.61),p-heterogeneity=0.72] but not group II cohort studies. While critics have suggested that previous meta-analyses are limited by exposure misclassification and unmeasured confounding, these factors would likely bias results towards the null. This updated meta-analysis, with more stringent inclusion criteria, continues to support an association between TCE exposure and kidney cancer.

back to top