Prognostic significance and role of thoracic lymph node metastasis based on Chinese expert consensus in esophageal cancer.

Background: The Chinese expert consensus on thoracic lymph node (LN) dissection in radical esophagectomy (Chinese Criteria, 2017 edition) was newly promoted. This study examined the prognostic significance and role of thoracic LN metastasis based on the Chinese Criteria for esophageal cancer.

Methods: Data of patients with thoracic esophageal squamous cell carcinoma (ESCC) who underwent curative esophagectomy in the West China Hospital from May 2005 to May 2015 were retrospectively analyzed. Patients' prognosis and clinicopathological features were compared to determine the role of Chinese Criteria and their relationship with Union for International Cancer Control (UICC)/American Joint Committee on Cancer (AJCC) 8th TNM staging.

Results: Overall, 2,285 qualified patients were divided into the no (n=1,148), skip (n=156), local (n=665), and mediastinal (n=316) metastasis groups according to the Chinese Criteria. Significant prognostic differences occurred among the four groups in all the thoracic and lower mediastinal ESCC patients (both P<0.001). The Chinese Criteria grouping was an independent prognostic factor for all thoracic [P<0.001; hazard ratio (HR) =1.261, 95% confidence interval (CI): 1.103-1.441], upper (P<0.001; HR =1.391, 95% CI: 1.264-1.530), lower mediastinal thoracic ESCC patients (P<0.001; HR =1.312, 95% CI: 1.257-1.370) and all thoracic ESCC after adjuvant therapy (P<0.001; HR =1.303, 95% CI: 1.221-1.390). Significant prognostic differences among Chinese Criteria groups occurred with N1 (P=0.014) and N2 (P=0.018) stages only. Significant differences in survival among N stages were found in local (P<0.001) and mediastinal (P=0.009) metastasis groups.

Conclusions: Our study was the first to report the Chinese Criteria in measuring the degree of thoracic LN metastasis. Similar to N-stage, the Chinese Criteria were confirmed as an independent prognostic factor for thoracic ESCC. Further confirmation of our findings is warranted.