Verifying the oncologic rationale of prophylactic central compartment neck dissection in the management of papillary thyroid carcinoma using a pathologic spectrum of nodal metastases characteristics. A Prospective Comparative study.

Background: Disease-free survival is the main outcome of interest considered when assessing the effectiveness of surgical management of papillary thyroid carcinoma (PTC). Specific characteristics of nodal metastases have been demonstrated to impact the risk of recurrence.

Objective: Verify the oncologic rationale of prophylactic central compartment neck dissection (pCCND) in the management of PTC by comparing the pathologic spectrum of lymph nodes in patient's undergoing pCCND vs. therapeutic CCND (tCCND).

Methods: Between May 2017 and October 2018, 257 patients underwent total thyroidectomy for PTC. pCCND was performed for clinically uninvolved nodes, and tCCND for clinically apparent nodal disease. Harvested metastatic nodes from each group were compared in terms of number, size, and the presence of extranodal extension. Cut-off values for the size and number were 2 mm and 5, respectively. Patients were followed until October 2023.

Results: 78 patients underwent tCCND. Whereas pCCND was performed in 179 patients. The mean number of nodes harvested in tCCND was 14 (9-31), and 9 (5-24) in pCCND (p < 0.0001). Node positivity was 84.6, and 37.4%, respectively (p < 0.0001). ≥5 metastatic nodes were harvested in 66.6% of tCCND vs. 7.5% of pCCND (p < 0.0001). 73% of tCCND had a metastatic node ≥2 mm in size vs. 2.5% of pCCND (p < 0.0001). Extranodal extension occurred in 25% of tCCND vs. 2.5% of pCCND (p = 0.01). Recurrence rate was 3.8% in tCCND vs. none in pCCND (p = 0.008).

Conclusion: Clinically inapparent nodal disease has a pathological spectrum with insignificant impact on disease recurrence. Therefore, pCCND does not seem to be oncologically meaningful.