e14678 Background: The 7th edition of the American Joint Committee on Cancer / Union International Against Cancer (AJCC/UICC) TNM staining system for esophageal cancer (EC) has been published. N descriptors are now divided into N0, N1, N2 and N3. In this study, we aimed to validate the prognostic ability of the new N staging system in patients with resectable EC and positive lymph nodes, and evaluate whether the new N staging system can help the decision-making for postoperative adjuvant therapy in this population. Methods: From 2002 to 2008, patients with stage T1-4N1-3M0 EC who underwent esophagectomy were retrospectively analyzed. EC was classified according to the new N staging system. Kaplan-Meier method and Cox regression analysis were employed to compare overall survival (OS). Results: A total of545 patients met the inclusion criteria: 346 (63.5%) received esophagectomy alone, 199 (36.5%) received esophagectomy and adjuvant radiotherapy, and 36.1% (197/545) received esophagectomy and adjuvant chemotherapy. Univariate analysis and multivariate analysis revealed significant difference in OS among patients with EC at different N stages (p<0.001). Significant difference in OS was also present among patients receiving radiotherapy (p<0.001) and those undergoing chemotherapy (p<0.001). Subgroup analysis indicated that postoperative adjuvant therapy did not significantly affect the OS among patients with EC at different N stages. Conclusions: Our results validated the prognostic ability of new N staging system. N descriptor is an independent prognostic factor in patients with resectable EC who were positive for lymph nodes. Further studies are required to clarify the role of new N staging system in the decision-making for postoperative adjuvant therapy in this population.
PO-0685: The value of postoperative adjuvant therapy for pT2-3 esophageal cancer treated by radical resection
