Elderly patients over 80 years undergoing colorectal cancer resection: Development and validation of a predictive nomogram for survival

BACKGROUND Surgery remains the primary treatment for localized colorectal cancer(CRC).Improving surgical decision-making for elderly CRC patients necessitates an accurate predictive tool.AIM To build a nomogram to predict the overall survival of elderly patients over 80 years undergoing CRC resection.METHODS Two hundred and ninety-five elderly CRC patients over 80 years undergoing surgery at Singapore General Hospital between 2018 and 2021 were identified from the American College of Surgeons–National Surgical Quality Improvement Program(ACS-NSQIP)database.Prognostic variables were selected using univariate Cox regression,and clinical feature selection was performed by the least absolute shrinkage and selection operator regression.A nomogram for 1-and 3-year overall survival was constructed based on 60%of the study cohort and tested on the remaining 40%.The performance of the nomogram was evaluated using the concordance index(C-index),area under the receiver operating characteristic curve(AUC),and calibration plots.Risk groups were stratified using the total risk points derived from the nomogram and the optimal cut-off point.Survival curves were compared between the high-and low-risk groups.RESULTS Eight predictors:Age,Charlson comorbidity index,body mass index,serum albumin level,distant metastasis,emergency surgery,postoperative pneumonia,and postoperative myocardial infarction,were included in the nomogram.The AUC values for the 1-year survival were 0.843 and 0.826 for the training and validation cohorts,respectively.The AUC values for the 3-year survival were 0.788 and 0.750 for the training and validation cohorts,respectively.C-index values of the training cohort(0.845)and validation cohort(0.793)suggested the excellent discriminative ability of the nomogram.Calibration curves demonstrated a good consistency between the predictions and actual observations of overall survival in both training and validation cohorts.A significant difference in overall survival was seen between elderly patients stratified into low-and high-risk groups(P<0.001).CONCLUSION We constructed and validated a nomogram predicting 1-and 3-year survival probability in elderly patients over 80 years undergoing CRC resection,thereby facilitating holistic and informed decision-making among these patients.