A NOVEL NOMOGRAM TO PREDICT RESECTABLE GASTRIC CANCER BASED ON PREOPERATIVE CIRCULATING TUMOR CELL (CTC).

Abstract

BACKGROUND Circulating tumor cells (CTCs) have been suggested to have an important prognostic role in gastrointestinal tumors. We developed a preoperative CTC-based nomogram to predict the prognosis of patients with resectable gastric cancer after surgery and established a risk stratification system based on the nomogram. METHODS From January 2012 to June 2017, we screened 258 gastric cancer patients treated with surgery from 1 center as the training cohort and 133 gastric cancer patients treated with surgery from another as the validation cohort, screened prognostic factors for the training cohort using univariate and multivariate COX risk proportional models, created predictive overall survival (OS) and recurrence-free survival (RFS) nomogram, and plotted the receiver operating curve (ROC) as well as the calibration curve for this nomogram in the training and validation cohorts. Risk score stratification was performed according to the nomogram, and overall survival (OS) survival curves were plotted for the low, medium, and high-risk groups using the Kaplan-Meier method. RESULTS The CTC positivity rate was 78.5% in all patients. CTC, TNM stage, and Ki-67 were the prognostic factors affecting OS and RFS after gastric cancer surgery. Nomogram consisted of these 3 variables. in the training group, the area under the curve (AUC) of nomogram at 1, 3, and 5 years OS were 0.918,0.829 and 0.813, respectively, and the area under the curve (AUC) for RFS was 0.900, 0884 and 0.839, respectively. There was a statistically significant difference in OS among the low, medium, and high-risk groups according to the risk stratification system constructed from nomogram scores (P<0.001). CONCLUSIONS Two nomograms based on preoperative CTC were established to predict overall and recurrence-free survival after resectable gastric cancer. The 2 nomograms had good discrimination and calibration and significant stratification ability of the risk stratification system established according to them.