Thyroid cancer histological subtypes based on tumor size: National perspective.

Abstract

Thyroid tumor size is an important prognostic factor. The aim of this study is to examine the histological subtypes and management of thyroid cancer based on tumor size (≤4 cm vs >4 cm). Retrospective cohort study utilizing the National Cancer Database, 2004-2014. A total of 152 387 patients were included, 13 614 (8.9%) of whom had a tumor size >4 cm. Histological subtypes of tumors >4 cm were: 69.6% papillary thyroid carcinoma, 17.5% FTC, 7.9% HCC, and 2.8% medullary thyroid carcinoma (MTC). High-volume hospitals for thyroid surgery were less likely to perform two-stage thyroidectomy, particularly for tumors ≤4 cm. Low-volume hospitals had a higher risk of staged thyroidectomy for MTC ≤4 cm (19.8%) compared with high-volume hospitals (8.7%) (P < .001). This study describes the prevalence of thyroid cancer subtypes. In the era of a conservative approach to differentiated thyroid carcinoma, there could be a potential increase in the risk of staged thyroidectomy.