Validation of a Nomogram for Predicting Overall Survival After Resection of Pulmonary Metastases from Colorectal Cancer at a Single Center

Background The goal of this study was to validate a survival nomogram at a single center, originally developed at multiple institutions in Japan, which combines readily available preoperative variables to predict overall survival after resection of pulmonary metastases from colorectal cancer. Methods An external patient cohort from a prospective pulmonary metastases database at the Aichi Cancer Center in Japan was used to test the validity of the pulmonary metastases from a colorectal cancer nomogram. The cohort included 58 consecutive patients who had surgery between January 1999 and December 2005. Nomogram predictions for 3- and 5-year overall survival were calculated for each patient and compared with actual survival. The concordance index was used as an accuracy measure. Results Data for all necessary variables were available for all patients. At the last follow-up, 30 patients were alive, with a median follow-up of 39 (range, 5-94) months. The 1-, 2-, 3-, and 5-year overall survival rates were 96.6, 84.5, 70.5, and 48.9%, respectively. The nomogram concordance index was 0.81 with excellent calibration for both 3- and 5-year overall survival rates. Conclusions The high predictive accuracy of pulmonary metastases from a colorectal cancer nomogram demonstrates that this predictive tool derived at multiple institutions can be applied to a small cohort of patients in a single center.