The survival outcomes of prophylactic lateral neck dissection for medullary thyroid carcinoma, a retrospective cohort study

Objectives: The purpose of this study was to evaluate the benefits of prophylactic lymph node dissection in medullary thyroid carcinoma (MTC) patients without radiographically lateral neck metastases.

Design: Retrospective cohort study.

Setting: Tianjin Medical University Cancer Institute and Hospital.

Participants: Patients who underwent primary surgery for MTC between 2011 and 2019 and without structural disease of the lateral neck preoperatively.

Main outcome measures: Locoregional recurrence, disease-free survival (DFS), and overall survival (OS) were examined.

Results: The patients were divided into two groups: the central lymph node dissection (CLND) only group and the prophylactic lateral lymph node dissection (PLND) group, which included CLND and ipsilateral lateral lymph node dissection (LLND). A total of 89 patients were included: 71 patients in the CLND group and 18 patients in the PLND group. Although there were no significant differences in age, gender, multifocality, capsule invasion or TNM stage between the two groups, the tumour size and preoperative median calcitonin levels were different. The recurrence rate was 4.2% for the CLND group and 5.6% for the PLND group (p > 0.05). DFS among the CLND and PLND groups was 95.4% and 94.4%, and OS among the groups was 100% and 94.1% (p > 0.05) at 5 years. The biochemical cure rates were similar.

Conclusions: PLND in the absence of structural disease of the lateral neck preoperatively is not associated with improved survival in patients with sporadic MTC.