Meta-analysis of risk factors for CCLNM in patients with unilateral cN0 PTC

BACKGROUND: In patients with papillary thyroid cancer (PTC) with clinical negative central lymph nodes (cN0), the use of prophylactic central lymph node dissection remains controversial. Contralateral central lymph node metastasis (CCLNM) occurs in 3.88–30.63% of patients with cN0 PTC. Therefore, the present meta-analysis aimed to obtain evidence for CCLNM risk factors in unilateral cN0 PTC. MATERIALS AND METHODS: Relevant studies were identified in the PubMed, SCIE, and Wanfang databases up to Oct 31, 2019. The included patients had undergone lobectomy or total thyroidectomy with bilateral central lymph node dissection and were diagnosed pathologically with PTC. Revman 5.3 software was applied for statistical analysis. RESULTS: Thirteen studies comprising 2449 patients were included. The factors associated with increased CCLNM risk in patients with cN0 disease were: age <45 years (odds ratio (OR) = 1.89, 95% CI = 1.43–2.49, P < 0.00001), male sex (OR = 1.67, 95% CI = 1.24–2.24, P = 0.0007), extrathyroidal extension (OR = 1.63; 95% CI = 1.17–2.28; P = 0.004), tumor size ≥1 cm (OR = 2.63, 95% CI 1.85–3.74, P < 0.00001), lymphovascular invasion (OR = 4.27, 95% CI = 2.47–7.37, P < 0.00001), and ipsilateral central lymph node metastasis (OR = 11.42, 95% CI = 5.25–24.86, P < 0.00001). However, no association was found for capsular invasion, multifocality, or Hashimoto thyroiditis. CONCLUSION: The meta-analysis identified that age <45 years, tumor ≥1 cm, male sex, lymphovascular invasion, extrathyroidal extension, and ipsilateral central lymph node metastasis are related to CCLNM in patients with unilateral CN0 PTC. These factors should influence the use of prophylactic central lymph node dissection in this group of patients.