The prognostic value of negative lymph node count for patients with gastric cancer who received preoperative radiotherapy

// Xinxing Li 1, * , Weigang Zhang 1, * , Xianwen Zhang 1, * , Haolu Wang 2 , Kai Xu 1 , Houshan Yao 1 , Jun Yao 1 , Xiaowen Liang 2 and Zhiqian Hu 1 1 Department of General Surgery, Changzheng Hospital, The Second Military Medical University, Shanghai 200003, China 2 Therapeutics Research Centre, School of Medicine, The University of Queensland, Princess Alexandra Hospital, Woolloongabba, QLD 4102, Australia * These authors have contributed equally to this work Correspondence to: Xiaowen Liang, email: x.liang@uq.edu.au Zhiqian Hu, email: huzhiq163@163.com Keywords: gastric cancer, preoperative radiotherapy, negative lymph node, survival Received: October 29, 2016      Accepted: December 27, 2016      Published: February 01, 2017 ABSTRACT Negative lymph node (NLN) count provides accurate prognostic information in patients with gastric cancer. However, it is unclear whether NLN still has prognostic value for patients received preoperative radiotherapy. In this study, Surveillance, Epidemiology, and End Results Program (SEER)-registered gastric cancer patients were used for analysis. Clinicopathological characteristics and survival time were collected. Univariate and multivariate Cox proportional hazards models were used to assess the risk factors for survival. NLN count was validated as an independent prognostic factor in both univariate and mulivariate analysis (P < 0.001). X-tile plots identified 12 as the optimal cutoff value to divide the patients into high and low risk subsets in terms of survival rate. Nomogram based on cancer-specific survival was successfully established according to all significant factors. The C-index was 0.630 (95% CI: 0.605–0.655). Subgroup analysis showed that NLN count was a prognosis factor for patients with advanced gastric cancer (stage ypII and ypIII). In conclusion, our results firmly demonstrated that NLN count was an independent prognostic factor for patients with gastric cancer who received preoperative radiotherapy. It provides more accurate prognostic information especially for patients with advanced gastric cancer (stage ypII and ypIII). Nomograms based on cancer-specific survival could be recommended as practical models to evaluate prognosis.