Impact of Subtype Variability on Clinical Features in Papillary Thyroid Cancer

Context Thyroid cancer comprises multiple subtypes and is broadly classified as aggressive or nonaggressive. While many studies have analyzed the clinical features of aggressive and nonaggressive subtypes, to the best of our knowledge, no study has focused on patients having more than 1 subtype concomitantly. Objectives We investigated the clinical features manifested when these subtypes and conventional types of thyroid cancer occur simultaneously in the same patient. Methods In this single-center, cross-sectional study, we analyzed 26 449 patients with thyroid cancer who underwent surgery for papillary thyroid cancer (PTC) between March 2009 and December 2021 in Korea. We categorized the patients into 5 groups according to the subtypes of PTC (conventional, aggressive, nonaggressive, conventional with aggressive, and conventional with nonaggressive). We compared the patient characteristics and clinical features among the groups and analyzed them statistically. Results Significant differences among the groups were observed based on the PTC subtypes. Patients with both conventional and aggressive subtypes exhibited more aggressive clinical features compared to those with the conventional subtype alone. In the same context, patients with both conventional and nonaggressive subtypes showed aggressive features compared to those with the nonaggressive subtype alone. Conclusion We concluded that patients with mixed subtypes had clinical features that were more severe than those with a single subtype, suggesting that postoperative management warrants caution.