Abstract A13: Papillary thyroid cancer clusters in North Carolina 1997-2017 Free

Thyroid cancer is the fastest-increasing cancer in the U.S., and papillary thyroid cancer (PTC) accounts for >80% of incident cases. Data also indicate that the incidence of PTC varies geographically. We investigated associations between residential location and PTC incidence using data from the North Carolina Central Cancer Registry to generate hypotheses about social and environmental factors related to etiology or diagnosis. Analyses included data on 961,111 individuals diagnosed with cancer between 1997 and 2017 (16,468 with PTC). We explored relationships between PTC and residential location at the time of diagnosis. Generalized additive models were used to predict PTC odds across North Carolina while adjusting for individual-level covariates. Cancer patients living in several regions of North Carolina (e.g., areas of the Western Piedmont and the Southern Coast) were up to 200% more likely to be diagnosed with PTC compared with individuals living elsewhere in the state. Patterns were not explained by geographic variation in individual age, sex, or race. We also examined temporal patterns in PTC incidence; these analyses suggest that geographic patterns vary over time and have diminished in recent years. To evaluate whether diagnostic factors explained observed patterns, we evaluated the average tumor size and disease stage in communities identified as having excess odds of PTC. Results of these analyses do not indicate that diagnostic factors are driving spatial patterns; tumor sizes and disease stage in these communities were similar to those in the state as a whole, which would not be expected if diagnostic bias explained variation. Cumulatively, our data suggest that localized environmental factors are influencing geographic distributions of PTC in North Carolina and provide exposure hypotheses for a future large-scale epidemiologic investigation.

Citation Format: Kate Hoffman, Heather M. Stapleton. Papillary thyroid cancer clusters in North Carolina 1997-2017 [abstract]. In: Proceedings of the AACR Special Conference on Environmental Carcinogenesis: Potential Pathway to Cancer Prevention; 2019 Jun 22-24; Charlotte, NC. Philadelphia (PA): AACR; Can Prev Res 2020;13(7 Suppl): Abstract nr A13.