Level II lateral neck dissection for papillary thyroid carcinoma: A retrospective cohort study.

BACKGROUND: For N1b papillary thyroid carcinoma (PTC) patients, lateral neck dissection encompassing levels Ⅱ-Ⅴ is generally recommended. However, routine level Ⅱ dissection is controversial given the low incidence of metastasis, and potential complications such as increased shoulder syndrome. METHODS: Retrospective analysis of consecutive patients with papillary thyroid carcinoma who underwent lateral neck dissection at a single institution from January 2019 to April 2021 was performed. Clinicopathological features such as age, gender, tumor location, tumor size, TgAb and TPOAb levels, capsular invasion, multifocality and lymph node metastases were examined to evaluate the occurrence of metastatic Level Ⅱ lymph nodes. RESULTS: Overall and occult level Ⅱ metastases were observed in 51.83% and 34.84% of cN1b PTC patients. Multivariant analysis showed that primary tumor, location of primary tumor and positive level Ⅴ can serve as independent risk factors of metastasis in level Ⅱ. For cN1b PTC patients not suspected of level Ⅱ lymph nodes preoperatively, independent risk factors for predicting occult level Ⅱ metastases may include the location of primary tumor, positive level Ⅲ and positive level Ⅴ. CONCLUSION: A significant number of patients with PTC and lateral neck disease experienced Level Ⅱ metastasis, with the location of primary tumor and multilevel lymph node involvement being the independent risk factors. If the tumor is less than 1 cm and located at lower 2/3 lobe, there is minimal possibility of level Ⅱ lymph node metastasis.