A Nomogram And Risk Classification System Forecasting The Cancer-specific Survival Of Neoadjuvant Rectal Cancer Patients

Objective : To investigate the factors influencing the survival prognosis of neoadjuvant rectal cancer patients,this study used rectal cancer data from the The Surveillance,Epidemiology,and End Results(SEER database)to construct prediction models to predict the 1-,3-and 5-year Cancer-specific survival(CSS)of rectal cancer.Methods:We downloaded clinical and pathology record data of rectal cancer in the SEER database from 2004 to 2014.Also,we used the clinicopathological data of all neoadjuvant rectal cancer patients collected at Shaanxi Provincial People’s Hospital between 2011 and 2015.Cox regression analysis was used to screen for significant risk factors.Based on these factors,we constructed a nomogram to predict CSS in patients with rectal cancer.Receiver operating characteristic curve(ROC),calibration curve,decision curve analysis(DCA),consistency index,area under curve(AUC)were used to assess the accuracy and reliability of the model.Using the X-tile to calculate optimal cut-off values for nomogram and develop a risk classification system,survival outcomes between two risk groups were analyzed by Kaplan-Meier.Results:We collected 7124 neoadjuvant rectal cancer patients in the SEER database and 142 neoadjuvant rectal cancer patients at the hospital.In the SEER database,Cox regression analysis showed that age,marital status,histological typing,degree of differentiation,yp T stage,yp N stage,longest tumor diameter,LN,PLN,and LNR were important prognostic factors.Based on the above results to build the nomogram,the c-index was 0.685(95%CI,0.674-0.696)in the training cohort,and the AUC was 0.702,0.729,and 0.712 for the 1-year,3-year,and 5-year CSSs respectively,the AUC of the validation cohort was 0.744,0.612,and 0.645.The calibration curves and DCA also showed acceptable results.After establishing the nomogram,we also established a risk stratification system.Patients were classified into 2 risk groups based on their total score,with statistically significant differences in survival(P < 0.05).Conclusion : Based on our findings,we developed a nomogram and risk stratification system to predict CSS in rectal cancer patients after neoadjuvant chemoradiotherapy.This model helps predict the prognosis of neoadjuvant rectal cancer.