Nomogram predicting the cancer-specific survival of early-onset colorectal cancer patients with synchronous liver metastasis: a population-based study

Purpose This research aimed to explore prognostic factors for early-onset colorectal cancer (EO-CRC) patients with liver metastasis (LM) and develop nomogram for predicting cancer-specific survival (CSS) probability quantitatively. Methods Our study included 4368 EO-CRC patients with LM registered in the Surveillance, Epidemiology, and End Results (SEER) database between 2010 and 2017. Potential prognostic factors for EO-CRC patients with LM were identified by multivariable Cox regression analysis. Prognostic nomogram was subsequently constructed based on these prognostic factors. The discriminative ability, calibration, and clinical usefulness of the nomogram were assessed by the area under the receiver operating characteristic (ROC) curves (AUC), calibration curves, and decision curve analysis (DCA). Results In the training cohort, marital status, primary tumor location, histopathological grade, T stage, number of metastatic organs, carcinoembryonic antigen (CEA), perineural invasion (PI), surgery of primary site, chemotherapy, radiation therapy, and metastatic lymph nodes ratio (LNR) were prognostic factors for cancer-specific mortality of EO-CRC patients with LM. The 1-, 2-, and 3-year AUC values of the prognostic nomogram were 0.777, 0.781, and 0.788, respectively. Calibration curves indicated acceptable agreement between nomogram-predicted survival and actual observed survival at 1, 2, and 3 years. DCA curves exhibited good positive net benefits in the prognostic model in most threshold probabilities at different time points. All of these results were reproducible in the validation cohort. Conclusions This study identified prognostic factors for EO-CRC patients with LM and developed a prognostic nomogram with good performance and clinical usability, which may help clinicians make better treatment decisions.