Abstract: Objective · To explore the prognostic factors for postoperative radiotherapy for patients with locally advanced esophageal squamous cell carcinoma (ESCC) and the effects of lymph nodes metastasis status on the survival of patients and failure modes of treatment.  Methods · Data of 121 patients with locally advanced ESCC who underwent radical resection and postoperative radiotherapy from 2006 to 2013 were collected. The overall survival (OS) and disease-free survival (DFS) were calculated using Kaplan-Meier. Univariate analysis and multivariate analysis were performed to investigate prognostic factors with the log-rank test and the Cox regression model. The differences in OS and recurrence patterns between patients with different lymph node metastasis status were compared.  Results · The median DFS of all patients was 22.57 months and median OS was 32.90 months. Multivariate analysis showed that KPS score, length of lesion, and positive lymph nodes ratio (pLNR) were independent prognostic factors for DFS and OS. For patients with positive lymph nodes, the median DFS of patients with pLNR ≤ 0.15 and pLNR>0.15 were 33.43 and 19.20 months (P=0.04). Patients without nodal skip metastasis (NSM) had better median OS than patients with NSM, but the difference was not statistically significant. OS was significantly worse in patients with pLNR>0.15 and NSM than in other patients with positive lymph nodes (median OS of 14.33 vs 32.50 months, P=0.02). pLNR had a better prognostic value for OS than the number of positive lymph nodes (AUC=0.673, P=0.04). Analysis of the failure patterns showed that more distant metastases were observed in patients with pLNR>0.15, while more local and regional recurrences were observed in patients with pLNR ≤ 0. 15.   Conclusion · The status of lymph nodes metastasis is associated with the prognosis of postoperative radiotherapy for patients with locally advanced ESCC. pLNR has a better prognostic value for OS for patients with positive lymph nodes. The recurrence pattern varies in patients with different pLNR after postoperative radiotherapy. The patients with high pLNR and NSM have poor prognosis.

Key words: esophageal squamous cell carcinoma, postoperative radiotherapy, lymph node metastasis, prognosis