Prognostic nomogram in patients with right-sided colon cancer after colectomy: a surveillance, epidemiology, and end results-based study

Abstract

Objective: This study aimed to develop and validate a nomogram for predicting overall survival (OS) in patients undergoing surgery for right-sided colon cancer (RCC).

Methods: We collected 25,203 patients with RCC from the Surveillance, Epidemiology, and End Results (SEER) database and randomly divided them into 7:3 training and internal validation set. Utilizing the Cox proportional hazards regression model, we constructed a nomogram based on prognostic risk factors. Furthermore, for external validation, we retrospectively followed up with 228 patients from Jiaxing First Hospital and assessed and calibrated the nomogram using the C-index and calibration curves.

Results: After identifying independent prognostic factors through univariate and multivariate analyses, a nomogram was developed. The c-index values of this nomogram differed as follows: 0.851 (95% CI: 0.845-0.857) in the training set, 0.860 (95% CI: 0.850-0.870) in the internal validation set, and 0.834 (95% CI: 0.780-0.888) in the external validation set, indicating the model's strong discriminative ability. Calibration curves for 1-year, 3-year, and 5-year overall survival (OS) probabilities exhibited a high level of consistency between predicted and actual survival rates. Furthermore, Decision Curve Analysis (DCA) demonstrated that the new model consistently outperformed the TNM staging system in terms of net benefit.

Conclusion: We developed and validated a survival prediction model for patients with RCC. This novel nomogram outperforms the traditional TNM staging system and can guide clinical practitioners in making optimal clinical decisions.

Keywords: SEER; nomogram; overall survival; prognosis; right-sided colon cancer.

Figure 1

LASSO Regression Analysis and Optimal Subset Regression Analysis. (A) Distribution of LASSO coefficients for all variables of RCC. (B) 8 variables identified by LASSO analysis. (C) Optimal subset regression model selecting 8 variables.

Figure 2

Nomogram for predicting 1-, 3-, and 5-year OS probabilities in patients with RCC after colectomy.

Figure 3

ROC curves and AUCs at 1, 3, and 5 years in the training set (A), internal validation set (B) and the external validation set (C) were used to estimate the prognostic accuracy of the nomogram.

Figure 4

Calibration graphs forecasting the 1-, 3-, and 5-year overall survival (OS) of patients within the training set (A), 1-year overall survival (B), 3-year overall survival(C). 5-year overall survival.

Figure 5

Calibration graphs forecasting the 1-, 3-, and 5-year overall survival (OS) of patients within the internal validation set (A), 1-year overall survival (B), 3-year overall survival (C). 5-year overall survival.

Figure 6

Decision curve analyses (DCA) of the nomogram and AJCC TNM staging system for 1-year (A), 3-year (B), and 5-year (C) overall survival. The x-axis represents the threshold probabilities, and the y-axis measures the net benefit. The horizontal line along the x-axis assumes that overall death occurred in no patients, whereas the solid purple line assumes that all patients will have overall death at a specific threshold probability. The Orange dashed line represents the nomogram. The green dashed line represents AJCC TNM staging system.

Figure 7

Calibration graphs forecasting the 1-, 3-, and 5-year overall survival (OS) of patients within the external validation set (A), 1-year overall survival (B), 3-year overall survival (C). 5-year overall survival.

Figure 8

Kaplan–Meier survival curves derived from nomogram-based groups of patients with RCC after colectomy. The p value (<0.0001) was determined by the log-rank test. (A) Kaplan–Meier survival curves derived from nomogram-based groups of patients with RCC after colectomy in the training set. (B) Kaplan–Meier survival curves derived from nomogram-based groups of patients with RCC after colectomy in the internal validation set. (C) Kaplan–Meier survival curves derived from nomogram-based groups of patients with RCC after colectomy in the external validation set.