Development and validation of a nomogram for predicting metachronous peritoneal metastasis in colorectal cancer: A retrospective study

Figure 1 Flow chart of the study. CRC: Colorectal cancer; ASA: American Society of Anesthesiologists; TNM: Tumor-Node-Metastasis; KRAS: Kirsten rat sarcoma viral oncogene homolog; NRAS: Neuroblastoma RAS viral oncogene homolog; BRAF: V-raf murine sarcoma viral oncogene homolog B; MSI: Microsatellite instability; LASSO: Least absolute shrinkage and selection operator.

Figure 2 Variables selection using least absolute shrinkage and selection operator binary logistic regression analysis. A: Least absolute shrinkage and selection operator (LASSO) coefficient of the 23 variables associated with metachronous peritoneal metastasis; B: Optimal parameter (λ) was obtained using 10-fold cross-validation and minimum criteria. When the minimum λ was 0.031, six nonzero coefficients were selected by LASSO regression. LASSO: Least absolute shrinkage and selection operator.

Figure 3 Nomogram for the probability of metachronous peritoneal metastasis based on six factors: Tumor site, histological type, pathological T stage, plasma levels of carbohydrate antigen 125, BRAF mutation, and microsatellite instability status. CA125: Carbohydrate antigen 125; MSI: Microsatellite instability; BRAF: V-raf murine sarcoma viral oncogene homolog B; MSI-L: MSI-Low; MSI-H: MSI-High.

Figure 4 Nomogram calibration curves showed good consistency between actual probability and predicted probability. A: Calibration curve for training cohort; B: Calibration curve for validation cohort.

Figure 5 Receiver operating characteristic curves of the nomogram for predicting metachronous peritoneal metastasis. A: The training cohort; B: Validation cohort.

Figure 6 Decision curve analysis for the metachronous peritoneal metastasis nomogram. The blue line represents this nomogram. When the threshold probability is between 1% and 90%, using this nomogram to predict metachronous peritoneal metastasis can achieve net benefit. m-PM: Metachronous peritoneal metastasis.