Esophageal cancer with distant lymph node metastasis: prognostic significance of metastatic lymph node ratio

The cervical and celiac lymph node metastases are defined as distant metastasis (Mlym) from thoracic esophageal carcinoma by TNM (primary tumor, regional lymph nodes, and distant metastasis) classification. The prognostic factors, however, of such distant node metastases are not fully understood. Of 85 patients with node-positive thoracic esophageal carcinoma who were treated with the same modalities of treatment, 31 (37%) had Mlym. Prognostic factors for long-term survival were analyzed by univariate and multivariate analyzes. Three patients are alive and free of cancer, and two patients survived over 5 years. Fifteen patients died of recurrent esophageal cancer and 11 patients succumbed to causes unrelated to esophageal cancer. Two patients with a single Mlym died without recurrence of esophageal cancer at 1.4 years and after more than 5 years, respectively. The 1-, 2-, 3-, and 5-year overall survival rates of all 31 patients were 64.5%, 24.8%, 17.0%, and 12.8%, respectively. The factors influencing survival rate were depth of invasion (pT1,2 vs. pT3,4) and metastatic lymph node ratio (< or =0.104 vs. > or =0.105). The survival rates were not influenced by number of lymph node metastasis, number of Mlym, or by metastatic lymph node ratio of Mlym. Among those two significant variables verified by univariate analysis, independent prognostic factor for survival determined by multivariate analysis was the metastatic lymph node ratio (risk ratio = 3.4, p = 0.0345). The results of this study indicate that a significant number of patients can be cured of esophageal carcinoma by extensive resection along with extended lymph node dissection even when the disease metastasizes to distant nodes.