Prognostic Variables in Thoracic Esophageal Squamous Cell Carcinoma

Background: Thoracic esophageal squamous cell carcinoma (TESCC) is an aggressive malignancy with a poor prognosis. The current American Joint Committee on Cancer (AJCC) TNM cancer staging system focusing on the effect of regional (N1) and nonregional lymph node (M1a and M1b) metastasis may need reappraisal. We investigated the role of the number of dissected and positive nodes in TESCC patients. Methods: A total of 109 TESCC patients (97 men; mean age of 62.3 years) who underwent surgical resection were retrospectively analyzed. The current AJCC TNM system and other lymph node classifications were used to subgroup these patients and analyze survival differences. Previously reported prognostic factors were evaluated. Results: Patients with positive lymph node metastasis had a poor prognosis (p < 0.001). There was a significant difference in survival among the 67 node-positive patients subdivided into subgroups with 1 to 3 and 4 or more positive nodes (p = 0.004). Multivariable Cox proportional hazard regression analysis identified four independent prognostic factors: difficulty in swallowing (p = 0.024), cigarette smoking (p = 0.003), number of positive lymph nodes (0, 1 to 3, and ≥4; p < 0.001), and gastric cardia invasion (p = 0.012). Total dissection of at least 20 lymph nodes was the minimal requirement to achieve accurate nodal staging. Conclusions: Dissection of more than 20 lymph nodes is mandatory in TESCC patients to achieve accurate staging. Positive lymph node metastasis of 4 or higher is a significant independent prognostic factor.