Thyroid Isthmusectomy with Prophylactic Central Compartment Neck Dissection is a Feasible Approach for Papillary Thyroid Cancer on the Isthmus

Background: The treatment for papillary thyroid cancer (PTC) has become more conservative, but still no specific guidelines exist for managing isthmic PTC. This study analyzed the outcomes from isthmusectomy in single isthmic PTC and compared it with those for patients who previously had undergone a total thyroidectomy. Methods: An isthmusectomy with prophylactic central compartment neck dissection (pCCND) was planned for a single isthmic PTC between 2014 and 2018 (isthmusectomy group). For cases with gross extrathyroidal extension (ETE) or multiple nodal metastasis, the procedure was converted to a total thyroidectomy. The study analyzed the characteristics and outcomes of the isthmusectomy group. Additionally, the results were compared with those of the isthmusectomy-feasible group who met the eligibility criteria for isthmusectomy among total thyroidectomies performed between 2009 and 2013. Results: Of the 90 patients in the isthmusectomy group, 81 received isthmusectomy and 9 had conversion to a total thyroidectomy. Microcarcinoma occurred in 72 cases and gross ETE in 3 cases. One patient showed occult satellite cancer, and seven patients showed more than five metastatic nodes. Transient hypocalcemia developed in five and patients and permanent hypocalcemia in one patient with total thyroidectomy. Of 46 patients who began hormone replacement postoperatively, 13 completely stopped taking medication during the follow-up period. Metachronous PTC was diagnosed for one patient 12 months after isthmusectomy. The isthmusectomy group and the isthmusectomy-feasible group showed similar clinicopathologic properties including multifocality, ETE, and nodal metastasis. However, the isthmusectomy group showed significantly less transient or permanent hypocalcemia and thyroid hormone dependency. Conclusions: Isthmusectomy with pCCND may be a feasible alternative for properly selected isthmic PTC, resulting in a better quality of life than total thyroidectomy.