[Analysis of related factors of prognosis after surgical treatment of patients with non-metastatic colorectal cancer and construction of a normagram prediction model].

ABSTRACT

Objective: To investigate the postoperative prognostic factors of non-metastatic colorectal cancer (non-mCRC), and construct a prognostic prediction model. Methods: A total of 846 patients with colorectal cancer who were admitted to the Cancer Hospital, Chinese Academy of Medical Sciences from July 1, 2014 to December 31, 2016 were included in the study. There were 314 patients in the metastatic colorectal cancer (mCRC) group and 532 patients in the non-mCRC group. The data of clinical characteristics, preoperative blood routine and common serum tumor markers for CRC tests were collected retrospectively. The disease-free survival time (DFS) data of patients in non-mCRC group were obtained by follow-up. Univariate and multivariate Cox regression analyses were used to clarify the independent risk factors of DFS, and then these factors were included to construct a nomogram prediction model. The concordance index (C index), receiver operating characteristic curve (ROC) and calibration curve were used to evaluate the performance of the model. Results: Platelet/lymphocyte ratio (PLR), neutrophil/lymphocyte ratio (NLR), carcinoembryonic antigen (CEA), carbohydrate antigen 19-9 (CA19-9) and carbohydrate antigen 242 (CA242) in the mCRC group were higher than those of the non-mCRC group, while the lymphocyte/monocyte ratio (LMR) was lower than that of the non-mCRC group (P<0.05). ROC analysis showed that the area under curve (AUC) of CEA, CA19-9, CA242, NLR, LMR and PLR for the diagnosis of mCRC were 0.775, 0.716, 0.712, 0.607, 0.591 and 0.556, respectively. Multivariate Cox regression analysis demonstrated that age, perineural invasion, pN stage and preoperative CA242 level were independent risk factors for DFS of non-mCRC patients (P<0.05). Based on this, a nomogram prediction model predicting 3 years of DFS for non-mCRC patients was constructed, its C index and AUC for non-CRC prognostic prediction were 0.710 and 0.733, respectively, higher than 0.696 and 0.701 of AJCC 7th edition TNM staging system. The calibration curve of nomogram showed that the predicted DFS rate was consistent with the actual DFS rate. Conclusions: Age, perineural invasion, pN stage and preoperative CA242 level are independent risk factors for 3-year DFS of non-mCRC patients. The nomogram prediction model constructed based on these four indictors has a good predictive performance and may provide prognosis evaluation reference for the patients with non-mCRC.