Surgical management and outcomes of T4a papillary thyroid carcinoma: a single-centre study of 602 cases

Objective This study aimed to investigate the clinical characteristics and risk factors associated with the disease progression of T4a papillary thyroid carcinoma (PTC). Methods In all, 602 patients (230 males; 372 females), aged 8-82 years, with T4a PTC who were admitted for initial surgery between April 2010 and September 2022 were retrospectively analysed. Results Tracheal invasion was observed in 271 (45.0%), oesophageal invasion in 190 (31.6%), recurrent laryngeal nerve (RLN) invasion in 516 (85.7%), and larynx invasion in 22 (3.7%) patients. The 5-year progression-free survival was 89.8%, and disease-specific survival was 96.0%, with a postoperative disease progression rate of 9.6% (54 patients) and mortality rate of 5.17% (29 patients). Disease recurrence was most likely to occur at the initial surgical site. Age >= 55 years, preoperative vocal cord paralysis, microvascular invasion, trachea invasion, and metastases to >5 cervical lymph nodes were independent risk factors for disease progression in patients with M0 stage. Male sex, preoperative vocal cord paralysis, microvascular invasion, specific pathological type, and laryngeal invasion were associated with an increased risk of disease progression for all T4a patients, while lobectomy, total thyroidectomy, tumour shaving on the RLN surface, total RLN resection, and absence of radioactive iodine therapy were not. Conclusions Surgery was the primary treatment for patients with stage T4a PTC and most patients had a satisfactory prognosis. Surgeons should comprehensively evaluate each patient before deciding the surgical approach.