Preoperative blood markers and intra-abdominal infection after colorectal cancer resection

Figure 1 Flowchart of the research study process. NLR: Neutrophil-lymphocyte ratio; PLR: Platelet-lymphocyte ratio; SII: Systemic immune-inflammation index; CEA: Carcinoembryonic antigen; ROC: Receiver operating characteristic; DCA: Decision curve analysis.

Figure 2 Diagnostic value of receiver operating characteristic curve evaluation index. CEA: Carcinoembryonic antigen; PLR: Platelet-lymphocyte ratio; NLR: Neutrophil-lymphocyte ratio; SII: Systemic immune-inflammation index.

Figure 3 Spearman correlation heat map. The darker the color, the stronger the correlation between the two indicators. NLR: Neutrophil-lymphocyte ratio; CEA: Carcinoembryonic antigen; PLR: Platelet-lymphocyte ratio; SII: Systemic immune-inflammation index.

Figure 4 Nomogram for predicting intra-abdominal infection in patients after radical colorectal cancer resection. For an individual patient, each variable corresponds to a single point at the top of nomogram (points). The total points were summed up by all single points and are indicated in the second line from the bottom (total points), and each total point corresponds to a probability of abdominal infection. NLR: Neutrophil-lymphocyte ratio; PLR: Platelet-lymphocyte ratio; SII: Systemic immune-inflammation index; CEA: Carcinoembryonic antigen.

Figure 5 Nomogram of intra-abdominal infection in training and validation sets. A: Receiver operating characteristic (ROC) curve of the nomogram in the training set; B: Calibration curve of the nomogram in the training set; C: Decision curve analysis (DCA) curve of the nomogram in the training set; D: ROC curve of the nomogram in the validation set; E: Calibration curve of the nomogram in validation set; F: DCA curve of the nomogram in the validation set. NLR: Neutrophil-lymphocyte ratio; PLR: Platelet-lymphocyte ratio; SII: Systemic immune-inflammation index; CEA: Carcinoembryonic antigen; AUC: Area under the curve.