P3.17-001 The Prognostic Analysis of Postoperative Radiotherapy for Esophageal Squamous Cell Carcinoma with Different Status of Lymph Node Metastasis

Abstract

Lymph node metastasis is a significant prognostic factor in patients with resected esophageal cancer. Although the role of postoperative radiotherapy has not been confirmed, a large number of studies have shown that postoperative radiotherapy can improve the local control and survival, especially for stage III and lymph node positive patients. This study retrospectively analyzed the prognostic factors of postoperative radiotherapy for locally advanced esophageal squamous cell carcinoma (ESCC), and evaluated the prognostic value of different status of lymph node metastasis. Data from 121 patients with locally advanced ESCC who underwent radical resection and received postoperative radiotherapy from 2006 to 2013 were reviewed retrospectively. OS and DFS were estimated using Kaplan-Meier. Univariate analysis and multivariate analysis were performed to investigate prognostic factors by the Log-rank test and the Cox regression model. The effects of different status of lymph node metastasis on OS and recurrence patterns were compared. The median DFS of all patients was 22.57 months, and median OS was 32.90 months. Multivariate analysis showed that Karnofsky Performance Status, length of tumor and positive lymph nodes ratio (LNR) were independent prognostic factors of DFS and OS. For patients with lymph nodes metastasis, LNR has better prognostic value for OS (AUC=0.673, P =0.04) compared with the number of positive lymph nodes (AUC=0.584 P=0.31). The median OS of patients with LNR≤ 15% and LNR>15% were 33.43 and 19.20 months, P =0.04. Patients without lymph node skip metastasis (NSM) had better OS than that with NSM, but the difference was not statistically significant. Among the patients with both LNR>15% and NSM, OS was significantly worse than other lymph node positive patients, with median OS of 14.33 vs. 32.50 months, P=0.02. The analysis of the treatment failure patterns showed that more distant metastases were observed in patients with LNR>15%, while more local and regional recurrences were observed with LNR≤15%. The status of lymph node metastasis was related to the prognosis of postoperative radiotherapy for locally advanced ESCC. LNR has better prognostic value for OS, treatment failure patterns varied in different LNR. The patients with both high LNR and NSM have significantly poorer prognosis.