Thyroid Lobectomy and Neck Dissection for N1b Papillary Thyroid Carcinoma

Patients with papillary thyroid carcinoma (PTC) with lateral neck metastases (N1b) are usually treated with total thyroidectomy (TT), neck dissection, and adjuvant radioactive iodine (RAI). This philosophy comes with higher risks of complications and sequela than thyroid lobectomy (TL) and neck dissection alone. There are no prior studies on patients from the Western hemisphere that compare survival and recurrence outcomes between these groups.

To compare recurrence and survival outcomes in propensity-matched TL vs TT + RAI patients who presented with ipsilateral N1b PTC at a tertiary cancer center in the US.

This cohort propensity-matched study was conducted at a single US tertiary cancer center included 37 TL patients and 37 of 561 TT + RAI patients (after excluding patients with M1 disease), with a median (IQR) follow-up of 113 (58-241) and 90 (48-185) months, respectively. Adult patients with PTC with lateral neck node metastases (N1b) were identified from a thyroid cancer database. The study included patients undergoing surgery at Memorial Sloan Kettering Cancer Center from 1986 to 2020, inclusive, and the study was conducted from 2024 to 2025.

Overall survival (OS), disease-specific survival (DSS), and recurrence-free survival (RFS).

Of 598 total individuals, the median (IQR) age was 41 (33-55) years, and 341 (57%) were female. The 5-year OS was 96.9% in the TL group and 96.8% in the TT + RAI group (hazard ratio [HR], 0.2; 95% CI, 0.03-1.58). The 5-year DSS was 96.7% in the TL group and 100% in the TT +RAI group. The 5-year RFS was 89.8% in the TL group and 88.9% in the TT + RAI group (HR, 1.48; 95% CI, 0.39-5.58). The survival rates did not change between 5 and 10 years.

This cohort study found that a select group of patients with N1b PTC treated with TL had no important difference in survival and recurrence outcomes compared with patients treated with TT + RAI. Therefore, TL is an effective and safe treatment option in carefully selected and appropriately counselled patients with N1b PTC with unilateral tumors and low-volume regional lymph node metastases without clinical extranodal extension.