Establishment and validation of a prognostic nomogram for patients with early-onset stage I-II colon cancer.

BACKGROUND: The aims of this study were to establish and validate a nomogram model for predicting the survival of patients with early-onset stage I-II colon cancer (CC).

METHODS: Data of eligible patients enrolled from 2012 to 2015 were extracted from the Surveillance, Epidemiology, and End Results (SEER) database. Patients were randomly allocated to training and validation groups in a 7:3 ratio. Significant prognostic factors were identified by univariate and multivariate analysis and a nomogram model constructed. The predictive performance of the nomogram was evaluated by the concordance index (C-index), calibration plots, and decision curve analysis.

RESULTS: Our study cohort comprised 3528 early-onset CC patients with stage I-II disease, 2469 of whom were allocated to the training cohort and 1059 to the validation cohort. Race, age, marital status, tumor grade, tumor size, tumor stage (T stage), and chemotherapy were considered the significant predictor by univariate analysis. Race, marital status, and T stage were found to be independent prognostic factors by multivariate analysis. The C-indexes of the nomogram were 0.724 and 0.692 in the training and validation cohorts, respectively. Likewise, the calibration plots showed good agreement regarding the probability of 3- and 5-year observed and nomogram-predicted overall survival in the training group. Decision curve analysis showed that the nomogram model was clinically practical and effective. Moreover, applying the nomogram enabled dividing of the patients into two cohorts with different risk scores. The low-risk group thus created had a better survival than the high-risk group.

CONCLUSIONS: We developed and validated a meaningful prognostic nomogram model for patients with early-onset stage I-II CC that clinicians can use to make better decisions for individual patients.