Nomogram Predicting the Survival of Young-Onset Patients with Colorectal Cancer Liver Metastases.

Background: Although the global prevalence of colorectal cancer (CRC) is decreasing, there has been an increase in incidence among young-onset individuals, in whom the disease is associated with specific pathological characteristics, liver metastases, and a poor prognosis. Methods: From 2010 to 2016, 1874 young-onset patients with colorectal cancer liver metastases (CRLM) from the Surveillance, Epidemiology, and End Results (SEER) database were randomly allocated to training and validation cohorts. Multivariate Cox analysis was used to identify independent prognostic variables, and a nomogram was created to predict cancer-specific survival (CSS) and overall survival (OS). Receiver operating characteristic (ROC) curve, C-index, area under the curve (AUC), and calibration curve analyses were used to determine nomogram accuracy and reliability. Results: Factors independently associated with young-onset CRLM CSS included primary tumor location, the degree of differentiation, histology, M stage, N stage, preoperative carcinoembryonic antigen level, and surgery (all p < 0.05). The C-indices of the CSS nomogram for the training and validation sets (compared to TNM stage) were 0.709 and 0.635, and 0.735 and 0.663, respectively. The AUC values for 1-, 3-, and 5-year OS were 0.707, 0.708, and 0.755 in the training cohort and 0.765, 0.735, and 0.737 in the validation cohort, respectively; therefore, the nomogram had high sensitivity, and was superior to TNM staging. The calibration curves for the training and validation sets were relatively consistent. In addition, a similar result was observed with OS. Conclusions: We developed a unique nomogram incorporating clinical and pathological characteristics to predict the survival of young-onset patients with CRLM. This may serve as an early warning system allowing doctors to devise more effective treatment regimens.