Prognostic Factors for Locoregional Recurrence in Patients with Thoracic Esophageal Squamous Cell Carcinoma Treated with Radical Two-Field Lymph Node Dissection: Results from Long-Term Follow-Up

Objective: To aim of this study was to determine the clinical and biological prognostic factors for locoregional recurrence (LRR) in patients with thoracic esophageal squamous cell carcinoma (ESCC) undergoing radical two-field lymph node dissection (2FLD). Methods: A total of 462 patients diagnosed with thoracic ESCC underwent radical esophagectomy between March 2001 and May 2010 at Sun Yat-Sen University Cancer Center. Clinical characteristics, CD44 expression, and tumor-infiltrating lymphocyte (TIL) levels were evaluated in 198 patients who underwent R0 dissection with long-term follow-up. Partial Cox regression analysis with leave-one-out cross-validation was performed to validate the selected risk factors. Results: With a median follow-up of 54 months, the 5-year local failure-free survival (LFFS) rate of 198 patients was 62.5%. Multivariate analysis revealed that T stage (p = 0.043), pathological positive tumor above the carina (p = 0.000), CD44 expression level (p = 0.045) and TIL level (p = 0.007) were prognostic factors for LFFS, while the Cox model with risk scores had an area under the curve value of 83.6% for the prediction of 5-year LFFS. The best cut-off value (sum score = 11.19) was used to determine the high- and low-risk groups, with patients at high risk having a significantly shorter 5-year LFFS than patients at low risk (p = 0.000). The LRR pattern revealed significantly high incidences of recurrent disease at the supraclavicular and cervical sites, mediastinum (above the carina), and anastomosis. Conclusions: Our predictive model was able to distinguish between patients at high risk for LRR and patients at low risk for LRR. LRR primarily involved the upper thorax and this area must be considered in future study designs for radical trimodality treatment.