A Prognostic Scoring System to Predict Survival Outcome of Resectable Colorectal Liver Metastases in this Modern Era

An individualized treatment decision is based on the accurate evaluation of clinical risk factors and prognosis for resectable colorectal liver metastases. The current study aimed to develop an effective nomogram to predict progression-free survival (PFS) and to design a treatment schedule preoperatively. The study enrolled a primary cohort of 532 patients with resectable colorectal liver metastases (CRLM) who underwent hepatic resection at two institutions and a validation cohort of 237 patients at two additional institutions with resectable CRLM between 1 January 2008 and 31 December 2018. A nomogram was created based on the independent predictors in the multivariable analysis of progression-free survival in the primary cohort. The predictive accuracy and discriminative ability of the nomogram were determined by the concordance index (C-index) and the calibration curve. The score was compared with the current standard Fong score and validated with an external cohort. The independent risk factors for CRLM patients identified in the multivariable analysis were tumor larger than 5 cm, more than one tumor, RAS mutation, primary lymph node metastasis, and primary tumor located on the right side. All five factors were considered in the nomogram. The C-index of the nomogram for predicting survival was 0.696. With external validation, the C-index of the nomogram for the prediction of the PFS was 0.682, which demonstrated that this model has a good level of discriminative ability. For high-risk patients (score > 16), neoadjuvant chemotherapy improved PFS and overall survival (OS) after hepatic resection. The current nomogram demonstrated an accurate performance in predicting PFS for resectable CRLM patients with liver-limited disease. Based on the current nomogram, high-risk patients (nomogram score > 16) might benefit from neoadjuvant chemotherapy.