Novel lymph node ratio predicts prognosis of colorectal cancer patients after radical surgery when tumor deposits are counted as positive lymph nodes: a retrospective multicenter study

// Jin Yang 1, * , Shasha Xing 1, * , Jun Li 2, 3 , Shengke Yang 4 , Junjie Hu 5 , Hao Liu 6 , Feng Du 7 , Jie Yin 8 , Sai Liu 9 , Ci Li 10 , Jiatian Yuan 2 , Bo Lv 2 1 Central Laboratory, Affiliated Hospital/Clinical Medical College of Chengdu University, Chengdu, China 2 General Surgery Department, Affiliated Hospital/Clinical Medical College of Chengdu University, Chengdu, China 3 Department of General Surgery, Zhongshan Hospital, Fudan University Colorectal Cancer Research Center, Shanghai, China 4 General Surgery Department, Sichuan Cancer Hospital, Chengdu, China 5 Gastrointestinal Tumor Surgery Department, Hubei Cancer Hospital, Wuhan, China 6 General Surgery Department, 2nd Affiliated Hospital of Jilin University, Changchun, China 7 Internal Medicine-Oncology, Cancer Institute, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China 8 General Surgery Department, Xuzhou Central Hospital, Xuzhou, China 9 Surgical Department of Gastrointestinal Diseases, Youan Hospital of Capital Medical University, Beijing, China 10 Department of Pathology, Clinical Medical College of Chengdu University, Chengdu, China * These authors have contributed equally to this work Correspondence to: Jun Li, email: junl_paper@sina.com Keywords: lymph node ratio, tumor deposits, colorectal cancer, prognosis Received: April 30, 2016 Accepted: September 02, 2016 Published: September 16, 2016 ABSTRACT The lymph node ratio (LNR), defined as the relation of tumor-infiltrated to resected lymph nodes, has been identified as an independent prognostic factor for colorectal cancer (CRC) after radical surgery. Recently, new guidelines propose counting tumor deposits (TDs) as positive lymph nodes (pLNs). The aim of this study was to investigate whether a novel LNR (nLNR) that considers TDs as pLNs can be used to accurately predict the long-term outcome of CRC patients. In this multicenter retrospective study, clinicopathological and outcome data from 2,051 stage III CRC patients who underwent R0 resection were collected between January 2004 and December 2011. Disease-free survival (DFS) and overall survival (OS) according to the nLNR category were analyzed using Kaplan-Meier survival curves. Univariate and multivariate analyses were performed to determine significant prognostic factors, and ROC curves were computed to measure the predictive capacity of the nLNR category. The 5-year DFS rates of nLNR1-4 were 68.3%, 48.4%, 33.3% and 16.5%, respectively ( P <0.0001), and the 5-year OS rate of nLNR1-4 were 71.8%, 60.1%, 42.7% and 21.8%, respectively ( P <0.0001). The area of under curve (AUC) of the nLNR was 0.686 (95% CI 0.663-0.710) and 0.672 (95% CI 0.648-0.697) for predicting DFS and OS. Our results demonstrate that the nLNR predicted long-term outcomes better than the LNR, npN and pN, using the cutoff points 0.250, 0.500 and 0.750.