Application of peripheral nerve invasion based nomogram model in predicting the prognosis of stage Ⅰ-Ⅲ early-onset colorectal cancer

Objective To evaluate the impact of peripheral nerve aggression (PNI) on prognosis in patients with stage Ⅰ-Ⅲ early-onset colorectal cancer (EO-CRC) and to create a PNI-based nomogram prediction model. Methods This study analyzed data on 5 920 EO-CRC patients aged 50 years and younger enrolled in the U.S. Surveillance, Epidemiology, and End Results (SEER) database from 2010 to 2015. The patients were divided into the training group (n=4 164) and the validation group (n=1 756) by a ratio of 7∶3. Kaplan-Meier survival curve was drawn and Cox proportional risk model was used for univariate and multivariate prognosis analysis. Based on the significant variables of the multivariate model, a nomogram was constructed, and the predictive ability was evaluated by receiver operating characteristic curve (ROC), calibration curve and decision curve analysis (DCA). Results Compared with PNI negative patients, PNI positive patients tended to be young, lesions located in the left colon, with poorer differentiation, higher TNM stage, chemotherapy intervention, and higher CEA level (P＜0.05). Kaplan-Meier curve suggested that PNI positive group had a worse prognosis than PNI negative group. Cox univariate analysis suggested that age, sex, degree of tumor differentiation, TNM stage, T stage, N stage, whether to receive radiation therapy, whether to receive chemotherapy, CEA level, maximum tumor diameter and PNI status were variables affecting the survival and prognosis of patients. Multivariate analysis showed that PNI was an independent prognostic indicator for patients with stage Ⅰ to Ⅲ EO-CRC (HR=1.73, 95%CI: 1.44-2.08, P＜0.01). The area under ROC curve of nomogram model based on PNI was more than 0.7 in both 3-year and 5-year lifetime. Conclusion PNI can be used as an independent prognostic marker in patients with stage Ⅰ-Ⅲ EO-CRC, and PNI-based nomogram model can be used as an effective prognostic tool.