Frozen Section-Guided Selective Ipsilateral Central Neck Dissection in Bethesda V-VI Thyroid Nodules: A Pilot Cohort Study Informing Surgical Extent

This observational retrospective cohort study was conducted in a tertiary referral endocrine surgery unit and was based on prospectively collected institutional data. The study included consecutive adult patients undergoing primary thyroid surgery for cytologically suspicious or malignant thyroid nodules, classified as Bethesda V or VI according to the Bethesda System for Reporting Thyroid Cytopathology.

The study was designed to evaluate whether an intraoperative strategy based on ipsilateral central neck dissection (ipsiCND) with frozen section analysis (FSA) could improve the adequacy of surgical treatment in selected patients with low-risk thyroid cancer, potentially reducing both overtreatment and undertreatment. The institutional protocol incorporating ipsiCND-FSA was introduced in September 2023. Patients treated before implementation of this protocol generally underwent total thyroidectomy according to the standard institutional practice in place at that time. After implementation of the protocol, hemithyroidectomy combined with ipsilateral central neck lymph node sampling and intraoperative frozen section analysis was systematically proposed as the preferred surgical strategy in appropriately selected patients. Total thyroidectomy remained an option for patients who declined the conservative approach after counselling regarding the malignant or suspicious nature of the thyroid nodule and the available surgical alternatives.

Eligible patients were adults aged 18 years or older with a solitary thyroid nodule measuring less than 2.5 cm in maximum diameter, classified as Bethesda V or VI on preoperative cytology, with a clinically node-negative neck documented by preoperative cervical ultrasound. Patients were considered only if they underwent primary thyroid surgery and had complete histopathological data available for the thyroid specimen and, when removed, central compartment lymph nodes. Patients with previous thyroid or neck surgery, known distant metastases at the time of surgery, incomplete clinical or pathological data relevant to the study endpoints, or reoperations such as completion thyroidectomy or secondary lymph node dissection were excluded.

All patients received detailed preoperative counselling and provided written informed consent before surgery. The information provided included the planned procedure, the possible need for intraoperative modification of the surgical strategy according to real-time findings and frozen section results, and the potential risks and benefits of the available surgical options. Patients also consented to the inclusion of their clinical and pathological data in the institutional database and to their use for research purposes. The study was conducted in accordance with the principles of the Declaration of Helsinki, followed good clinical practice standards, and was approved by the local Ethics Committee under protocol PA-1-RETRO-2026-TBD. Reporting was planned in accordance with the STROCCS recommendations for observational studies.

All surgical procedures were performed or supervised by experienced endocrine surgeons. Intraoperative nerve monitoring was routinely used in all cases as part of the standard institutional practice. The extent of thyroid surgery, either total thyroidectomy or lobectomy/isthmectomy, and the strategy for management of the central neck compartment were planned preoperatively according to cytological diagnosis, imaging findings, clinical risk profile, and institutional practice. In patients managed according to the ipsiCND-FSA protocol, the operative plan could be modified intraoperatively on the basis of frozen section findings.