Risk factors for lateral cervical lymph node metastasis in medullary thyroid carcinoma.

: To investigate risk factors of lateral cervical lymph node metastasis (LLNM) in patients with medullary thyroid carcinoma (MTC). : Published studies regarding clinicopathological factors of LLNM in MTC were searched in PubMed, Web of Science, Embase, Cochrane library, Wanfang date and CNKI. Statistical analysis was performed using Stata 14.0 software. The mean and standard deviation from the sample size, range, median, and interquartile range was estimated. Odds ratio () or standard mean difference () with 95% confidence interval () of related factors were analyzed by fixed/random-effects models. Egger's test and Begg's test were applied to assess the publication bias of the literature. This study was registered with PROSPERO (CRD42021254955). : Fifteen studies involving 1424 patients were included in the analysis, among whom 543 cases had LLNM (38.13%). Meta-analysis revealed that an increased risk of LLNM was associated with male gender (1.64, 95%: 1.29-2.09, 4.06, 0.01), tumor diameter≥1cm (5.09, 95%: 2.43-10.67, 4.31, 0.01), multifocality (2.55, 95%: 1.79-3.61, 5.22, 0.01), capsule invasion (7.80, 95%: 4.84-12.55, 8.46, 0.01), extracapsular extension (9.46, : 5.66-15.81, 8.58, 0.01), cervical central lymph node metastasis (23.58, : 9.44-58.87, 6.77, 0.01), elevated preoperative calcitonin (1.17,95%: 0.67-1.67, 4.56, 0.01), spiculated margin on ultrasonography (4.32, 95%: 2.43-7.68, 4.99, 0.01), irregular shape on ultrasonography (6.81, : 3.64-12.73, 6.01, 0.01); while age ≥ 45 years (=1.22, 95%: 0.65-2.29, 0.62, >0.05), elevated preoperative carcinoembryonic antigen (0.95, : -0.48-2.38, 1.30, >0.05) and calcification on ultrasonography (1.28, 95%: 0.75-2.18, 0.92, >0.05) were not associated with LLNM. : Male gender, tumor diameter≥multifocality, capsule invasion, extracapsular extension, central lymph node metastasis, elevated preoperative calcitonin, spiculated margin and irregular shape on ultrasonography are risk factors for LLNM in MTC, when these clinical and ultrasonic features are present, lateral neck lymph node dissection is recommended.