Mark Purdue

PhD

DCEG, NCI

Senior Investigator

PLCO (Learn more about this study)

2020-0003

Sep 18, 2020

Serum levels of per- and polyfluorinated substances and risks of non-Hodgkin lymphoma and thyroid cancer

Per- and polyfluoroalkyl substances (PFAS) – chemicals used in the manufacture of non-stick cookware, stain- and waterproof fabrics, firefighting foams and other applications – are now widespread soil and water contaminants, detectable in the blood of approximately 98% of the US population. A 2017 IARC Monograph review classified perfluorooctanoic acid (PFOA), one of the most produced and studied PFAS, as a possible human carcinogen (Group 2B), based mainly on evidence for cancers of the kidney and testis. However, epidemiologic findings also suggest that predicted PFOA exposure may be related to risks of non-Hodgkin lymphoma (NHL) and thyroid cancer. Additional epidemiologic studies are needed to clarify the relationship between PFAS exposures and these cancers, ideally involving larger sample sizes and a direct serologic assessment of these chemicals. It is also important to evaluate whether PFOA-related cancer risks exist within study populations with lower exposure levels akin to the general population, such as the PLCO Trial. To that end, we propose to conduct a case-cohort study investigating the relationship between pre-diagnostic serum PFAS levels and risks of NHL and thyroid cancer. This study will be the largest PFAS investigation of these cancers to date and the first to directly measure concentrations of PFOA and other PFAS in serum, as opposed to indirect exposure estimates used in past studies. With these strengths, this study is expected to provide important new insight into whether elevated PFAS exposures in the general population are associated with risk of these cancers.

As a secondary aim we will explore histology-specific PFAS associations for two major NHL subtypes (diffuse large B-cell lymphoma, follicular lymphoma) and thyroid cancer of papillary histology.

Aim 1. Investigate the relationship between serum levels of selected PFAS [2-(N-methyl-perfluorooctane sulfonamido) acetic acid; perfluorobutane sulfonic acid; perfluorohexane sulfonic acid; perfluoroheptanoic acid; n-perfluorooctane sulfonic acid; perfluoromethylheptane sulfonic acids (methyl branched PFOS); n-perfluorooctanoic acid; branched perfluorooctanoic acids (branched PFOA); perfluorononanoic acid] and risk of NHL.

Aim 2. Investigate the relationship between serum levels of selected PFAS and risk of thyroid cancer.