Prognosis of Patients With Pathologic T0 N+ Esophageal Squamous Cell Carcinoma After Chemoradiotherapy and Surgical Resection: Results From a Nationwide Study

Background. Few data are available on the survival outcomes of patients with esophageal squamous cell carcinoma who achieve complete response at the primary site but have residual nodal metastases after chemoradiotherapy. We sought to assess the survival of esophageal squamous cell carcinoma patients with ypT0 N+ disease. Methods. Esophageal squamous cell carcinoma patients treated with chemoradiotherapy and esophagectomy were identified from the Taiwan Cancer Registry between 2008 and 2013. We compared the clinical and survival data of ypT0 N+ and ypT0 N0 patients. The median number of dissected nodes (n = 20) was used as the cutoff to classify the extent of lymph node dissection (LND). Survival data were analyzed with the Kaplan-Meier method and Cox proportional hazards regression models. Results. The study included 369 ypT0 patients (50 ypT0 N+ [13.6%] and 319 ypT0 N0 [86.4%]). The 3-year overall survival was significantly lower in ypT0 N+ patients (30.1%) than in ypT0 N0 patients (55.9%, p < 0.001). Multivariate analysis showed that a higher number of positive lymph nodes (ypN2/N3 vs ypN1) was a strong adverse prognostic factor (hazard ratio, 3.76; p = 0.011) in ypT0 N+ patients. The extent of LND was identified as an independent predictor of survival in patients with ypT0 N0 disease (low vs high; hazard ratio, 1.49; p = 0.045). A stepwise decrease in 3-year overall survival rates was observed in the following groups: ypT0 N0 with high LND (61.2%), ypT0 N0 with low LND (50.3%), and ypT0 N+ (30.1%, p < 0.001). Conclusions. At least 13.6% of ypT0 patients have lymph node metastases, which carry adverse prognostic implications. The number of positive nodes is the most important prognostic factor in this group. (C) 2016 by The Society of Thoracic Surgeons