Analysis of risk factors for lateral lymph node metastasis in papillary thyroid carcinoma: A retrospective cohort study.

Objective: To investigate the risk factors for lateral lymph node metastasis (LLNM) in papillary thyroid carcinoma (PTC).

Methods: A retrospective analysis of 209 patients with PTC who underwent primary surgery at the Beijing Friendship Hospital affiliated with Capital Medical University from November 2014 to November 2018 was performed. The patients were divided into the LLNM group and the non-LLNM group. The clinical and pathological characteristics of the patients were analysed. The risk factors for LLNM were analysed by univariate and multivariate analyses.

Results: The incidence of LLNM was 13.4% in PTC patients. Univariate analysis showed that the maximum diameter of the primary tumour > 2 cm (P < 0.001), bilateral primary tumour (P = 0.020), extrathyroidal extension (ETE) (P < 0.001), central lymph node metastasis (CLNM) (P < 0.001), and CLNM number ≥ 5 (P < 0.001) were significantly associated with LLNM. Multivariate logistic regression analysis showed that the maximum diameter of the primary tumour > 2 cm, ETE, and CLNM were independent risk factors for LLNM (OR values were 3.880, 5.202, and 4.474, respectively). There were 6 patients with skip lateral cervical lymph node metastasis, accounting for 21% of all LLNM patients.

Conclusion: This study revealed several independent risk factors for predicting LLNM in PTC patients, such as the maximum diameter of the primary tumour > 2 cm, ETE and CLNM. Lateral neck dissection may be recommended in PTC patients with those risk factors. Paying attention to the occurrence of skip lateral cervical lymph node metastasis during the clinical diagnosis and treatment processes is necessary.