Necessity of Intraoperative Level IIA Lymph Node Dissection in Patients with Carotid Body Tumors: A Retrospective Study of 126 Cases

Background: Carotid body tumors (CBTs) are relatively uncommon neoplasms that rarely have malignant potential. However, malignant CBTs (MCBTs) are still associated with a poor prognosis and the treatment is still challenging clinically. Therefore, we evaluated the necessity of intraoperative level IIA lymph node dissection in patients with CBT. Methods: The clinical characteristics, intraoperative details, and pathological diagnosis of 126 CBT patients who had undergone surgery were retrospectively reviewed. The patients were divided into 2 groups according to whether level IIA lymph node dissection was performed. The prognosis was analyzed using Kaplan-Meier curves and Cox model multivariate survival analysis. Results: Among the 126 patients, 7 patients (10.3%) in the selective lymph node dissection (SLND) group (68 patients) were diagnosed with MCBTs with evidence of lymph node metastasis. Two patients (3.4%) in the lymph node nondissection (LNND) group (58 patients) were diagnosed with MCBTs later after the second operation because they could not be diagnosed as malignant initially because of the lack of lymph node pathology results although the pathology of the primary lesion showed features of malignancy. The SLND group had a significantly higher relapse-free survival rate than the LNND group (94.1% vs. 79.3%, p = 0.021). Patients with a confirmed diagnosis had a better prognosis than those with insufficient evidence of a malignancy due to the lack of lymph node information. Twenty-nine patients in the SLND group and 26 patients in the LNND group had postoperative nerve injuries, with no significant difference between the groups (p = 0.879). Conclusion: Intraoperative dissection of level IIA lymph nodes around the tumor in CBT patients can help improve the diagnosis and prognosis of MCBTs without causing additional cranial nerve injury.