Prevalence, Risk Factors And Location Of Skip Metastasis In Papillary Thyroid Carcinoma: A Systematic Review And Meta-Analysis

BACKGROUND: Skip metastasis is a special type in cervical lymph node metastasis (LNM) of patients diagnosed with papillary thyroid carcinoma (PTC) which induced poor prognosis. There are few studies about skip metastasis and conclusions remained uncertain. Therefore, this study aims to explore the frequency and to investigate risk factors of skip metastasis in PTC. METHODS: Through searching the keyword by PubMed and Embase databases which articles published up to 1(st) August 2018 about skip metastasis in papillary thyroid carcinoma, we extract data in order to assure whether those materials meet the criteria. RESULTS: The prevalence of skip metastasis is 12.02% in light of our meta-analysis of 18 studies with 2165 patients. The upper pole location (RR = 3.35, 95% CI =1.65–6.79, P = 0.0008) and tumors size ≤1 cm (RR = 2.65, 95% CI =1.50–4.70, P = 0.0008) are significantly associated with skip metastasis, whereas lymphovascular invasion (RR = 0.33, 95% CI =0.15–0.75, P = 0.0083) exists lower rate of skip metastasis. Multifocality, gender, age, bilaterality, thyroiditis and Extrathyroidal extension (ETE) are insignificantly associated with skip metastasis. Level II and level III are the most frequently affected areas. CONCLUSION: The lateral compartment should be carefully examined especially for those PTC patients who present primary tumors in the upper lobe with a primary tumor size ≤10 mm which could be detected with skip metastasis.