[Molecular subtyping and clinical characteristics of patients with reoperated papillary thyroid carcinoma]

Objective: To explore the reoperation cause and molecular classification of patients reoperated for papillary thyroid carcinoma (PTC). Methods: This is a retrospective case series study. Clinical data from 102 PTC patients who underwent reoperation at the Department of Head and Neck Surgery, Sun Yat-sen University Cancer Center were collected between February 2019 and December 2024. The cohort comprised 26 males (25.5%) and 76 females (74.5%), with initial age of (33.1±12.2) years (range: 9 to 67 years). At initial surgery, 25.5% (26/102) exhibited extrathyroidal extension, 52.0% (53/102) had multifocal tumors, and 19.6% (20/102) had metastatic lymph nodes with extranodal extension. AJCC staging classified 95.1% (97/102) as stage Ⅰ, 2.9% (3/102) as stage Ⅱ, and 2.0% (2/102) as stage Ⅲ. Standardized primary tumor resection was performed in 81.4% (83/102), prophylactic central compartment lymph node dissection (LND) in 89.2% (91/102), and therapeutic lateral LND in 47.1% (48/102). Data on recurrence, genetic alterations, reoperation intervals, and clinical features of multiple recurrent PTC cases were analyzed. Results: Among 102 patients, 81.4% (83/102) presented with lateral neck metastases, 48.0% (49/102) with central compartment metastases, and 22.6% (23/102) with residual thyroid lobe recurrence at reoperation. Reoperation occurred within 6 months postoperatively in 18.6% (19/102) and after 6 months in 81.4% (83/102). Genetic detection revealed BRAF mutation in 63.7% (65/102), RET fusions in 19.6% (20/102), and TERT promoter mutations in 8.8% (9/102). During reoperation, 88.2% (90/102) underwent therapeutic lateral LND, and 39.2% (40/102) required residual gland resection. Twelve patients received multiple surgeries, including 4 cases with BRAF+TERT mutations, 4 with RET fusions, and 4 with BRAF mutation alone. Conclusions: The reasons for the reoperation of PTC mainly include recurrence and complementary surgery. Genetic alterations such as BRAF mutation and RET fusion are common in PTC patients requiring reoperation.