Development and validation of nomograms for prediction of overall survival and cancer-specific survival of patients with Stage IV colorectal cancer.

BACKGROUND: Surgical resection of patients with resectable Stage IV colorectal cancer (CRC) is regarded as first choice if possible. However, its influence on overall survival (OS) has not been thoroughly explored. In this study, we aimed to construct nomograms to help predict 1-, 3- and 5-year OS rate and colorectal cancer-specific survival (CCSS) rate.

METHODS: A total of 2996 cases who underwent primary and metastatic resection were selected in the study from surveillance, epidemiology and end results (SEER) database. About 48 Stage IV CRC patients after resection from the Fudan University Shanghai Cancer Center (FUSCC) were assigned as an independent external validation group. Log-rank and multivariate Cox regression analysis were used. The competing-risks model was used to estimate the cumulative incidence of death. Nomograms were built for prediction of OS and CCSS after surgical resection in patients with Stage IV CRC.

RESULTS: The 1-, 3- and 5-year probabilities of OS were 76.6%, 41.4% and 23.2%, respectively. The 1-, 3- and 5-year colorectal cumulative incidence of death were 23.0%, 54.9% and 71.3%, respectively. The calibration curves for probability of 1-, 3- and 5-year OS and CCSS showed optimal agreement between nomogram prediction and actual observation, and the Harrell's C-indexes for the nomograms to predict OS and CCSS were 0.662 and 0.650, respectively. For FUSCC validation set, the C-index for this model to predict OS was 0.657.

CONCLUSION: Nomograms for prediction of OS and CCSS of patients with Stage IV CRC who underwent primary and metastatic resection were built. Performance of the model was excellent. These nomograms may be helpful for patients and physicians when making a decision.