LATEBREAKER
Cancer
Evaluation of dose-response between serum PFOA and testicular and kidney cancer Alexander Riordan* Alexander Riordan Michael Anthony Capello Elizabeth Best
Introduction: In 2017, IARC classified perfluorooctanoic acid (PFOA) as a possible carcinogen for testicular and kidney cancer. Since then, two studies attempted to meta-analyze risk of these cancers by dose of PFOA (i.e. serum concentration), but only did so qualitatively or via simple methodology. We re-analyzed the dose-response relationships with a more thorough method, meta-regression, while also incorporating data from a newly published study. Methods: A systematic literature search was conducted to identify epidemiological studies examining the association of PFOA concentrations and risk of testicular and kidney cancer, specifically with quantitative dose estimates and associated risks. Upon retrieval, categorical dose estimates were converted to continuous estimates, using the midpoint of each category. Subsequently, doses and corresponding risk estimates were meta-regressed, using random effects methods. Results/Conclusion: A total of seven studies each for testicular and kidney cancer were identified, with variation on how dose was reported. Meta-regression for testicular cancer yielded a beta (slope) of 0.034 (p=0.03) per 100 ng/mL-year increase in serum PFOA concentration, incorporating a 10-year lag. For doses reported as ng/mL, the meta-regression beta was 0.0087 (p=0.05) per 1 ng/mL increase in PFOA serum concentration. Meta-regression of cumulative doses associated with kidney cancer yielded betas of 0.0032 (p=0.48), 0.0052 (p=0.47), and 0.028 (p=0.89) per 100 ng/mL-year increase in serum PFOA concentration, accounting for no lag, 10-year, and 20-year lag, respectively. Lastly, a beta of 0.0014 (p=0.21) was observed per 1 ng/mL increase of serum PFOA and increase risk of kidney cancer. All regression models demonstrated low evidence of heterogeneity as all I2 were below 22%, except one model. Our results demonstrate overall flat dose-response trends between increasing serum PFOA concentrations and risks of testicular and kidney cancer. These results are consistent with conclusions from other qualitative trend evaluations, in that associations between serum PFOA and kidney/testicular cancer are tenuous.