Trend analysis of thyroid carcinoma incidence: a retrospective analysis of 2705 cases from an endemic goiter region Runnig title: Trend analysis of thyroid carcinoma an endemic goiter region

Abstract

Introduction: To provide further data from a population with different genetic background for the contrary views on the ensuing question of “whether iodine status influence the onset and course of thyroid cancer (TC)” by examining trends in TC incidence and prevalence of main sub types of TC in a population from formerly iodine deficient geographic area in Turkey. Methods: Data were retrieved for 2,705 patients (2,161 female, 544 male) who were diagnosed with histopathologically confirmed thyroid cancer at Karadeniz Technical University Farabi Hospital, a university hospital serving a geographic region which remains an endemic goiter area and was formerly iodine-deficient, shortly after mandatory national salt iodization, between 2000 and 2018. Age, gender, subtype, tumor size, stage, and the changes and trends over the years were retrospectively evaluated. Results: Thyroid cancer rates had a trend of increase from 2000 to 2012 and then began to decline. In our region, PTC is more prevalent (93.5%). Among all thyroid cancers, the ratio of micro papillary thyroid cancer (mPTC) is 46.5%, FTC is only 3.5%. mPTC (tumor size ≤10 mm) (49.8%) and macroPTC (tumor size >10 mm) (50.2%) are approximately equal in proportion, and these ratios remained similar over the years covered in this analysis. Stage I PTC is 95.3%. M0 PTC is %98.9. Conclusion: Data from this retrospective epidemiologic study indicates that the rate of PTC is notably high and TC may have a more benign course in our endemic goiter region probably due to iodine supplementation that may affect late-stage thyroid carcinogenesis.