Evidence-based integration of clinicopathological factors with the risk of papillary thyroid carcinoma lateral cervical lymph node metastasis: systematic review and meta-analysis and subgroup study.

Background: Papillary thyroid carcinoma (PTC) is characterised by a high incidence and high burden. Although surgery combined with adjuvant radioiodine therapy can significantly improve the prognosis of PTC patients, the indication of prophylactic lateral neck lymph node dissection is still controversial. In addition, the sensitivity of preoperative ultrasound for lateral cervical lymph node metastasis (LLNM) is low, so it is important to identify the independent risk factors for LLNM. This study aimed to investigate lateral lymph node metastasis in PTC. A systematic review and meta-analysis of risk factors for clinicopathological, ultrasound, and related features of LLNM were performed.

Methods: The clinical pathological, ultrasonic, and related risk factors of LLNM in PTC were studied by database search, and the risk factors of LLNM in PTC were analyzed by RevMan5.2 software.

Results: Among a total of 40,190 patients, 4,991 had LLNM in 24 studies. Gender [odds ratio (OR) =1.51; 95% confidence interval (CI): 1.34-1.70; P<0.001], extrathyroidal extension (ETE) (OR =4.16; 95% CI: 2.82-6.14; P<0.001), tumor size (OR =0.35; 95% CI: 0.20-0.59; P<0.001), multifocality (OR =1.94; 95% CI: 1.50-2.52; P<0.001), central lymph node metastasis (CLNM) (OR =5.38; 95% CI: 2.62-11.07; P<0.001), capsular invasion (OR =0.07; 95% CI: 0.05-0.08; P<0.001), tumor location (OR =1.84; 95% CI: 1.63-2.09; P<0.001), calcification (OR =1.97; 95% CI: 1.34-2.91; P<0.001), and echogenicity (OR =1.55; 95% CI: 1.16-2.08; P<0.001) were significantly associated with LLNM.

Conclusions: The following clinicopathological and ultrasonic features were significantly correlated with lateral neck lymph node metastasis, such as male, ETE, tumor size >2 cm, multifocality, CLNM, capsular invasion, high tumor location, calcification, and hyperechoic. It is suggested that for suspected metastatic lymph nodes, lateral neck lymph node dissection can be considered in patients with the above risk factors to reduce the recurrence and distant metastasis of PTC. However, this study has some limitations, such as no new biomarkers were included, high heterogeneity, and geographic bias.