Modulating the extension of thyroidectomy in patients with papillary thyroid carcinoma pre-operatively eligible for lobectomy: reliability of ipsilateral central neck dissection

Purpose: Pre-operative work-up and macroscopic intraoperative inspection could overlook occult central neck nodal metastases in patients with papillary thyroid carcinoma (PTC). An occult N1a status is able to change the initial risk stratification in small, clinically unifocal PTC potentially scheduled for thyroid lobectomy (TL) making total thyroidectomy (TT) the preferable option. We aimed to verified the reliability of an intraoperative management protocol based on frozen section examination (FSE) of ipsilateral central neck nodes (IpsiCND) to identify, among patients scheduled for TL, those who could benefit of a more extensive surgical resection (TT plus bilateral central neck dissection -CND-). Methods: Thirty PTC patients preoperatively classified as T1N0 underwent TL plus IpsiCND-FSE (TL-group). In case of positive FSE, TT plus bilateral CND was accomplished during the same surgical procedure. A comparative analysis was performed between TL-group and a control group (C-group), who underwent TT plus IpsiCND-FSE, matched by a propensity score analysis. Results: Nodal metastases (>2 mm) were found at final histology in 5/30 patients in the TL-group and in 6/30 in the C-group (p = 1.00). Micrometastases (≤2 mm) were retrieved in 5/30 TL-group patients and in 4/30 C-group patients (p = 1.00). Final histology staged as pN1a 10 (33.3%) patients for each group. FSE correctly identified five patients with occult nodal metastases >2 mm (16.6%) in TL-group, who underwent TT plus bilateral CND during the same surgical procedure. No permanent complications occurred. At a mean follow-up of 22.2 months, no local and/or nodal recurrence were observed. Conclusions: Intraoperative assessment of N status obtained with IpsiCND plus FSE allows for an accurate risk stratification. IpsiCND plus FSE real time modulated thyroidectomy seems a safe and effective surgical strategy reducing the need of a subsequent completion surgery and, theoretically, the risk of local recurrence.