Development and Validation of a Prognostic Nomogram in AFP-negative hepatocellular carcinoma

The aim of this study is to establish and validate an effective prognostic nomogram in patients with AFP-negative hepatocellular carcinoma (HCC). The nomogram was based on a primary cohort that consisted of 419 patients with clinicopathologically diagnosed with HCC, all the data was gathered from 2008 to 2014 in Sun Yat-sen University Cancer Center. All the model factors were determined by univariate and multivariate Cox hazard analysis. The concordance index (C-index) and calibration curve were used to determine the predictive accuracy and discriminative ability of the nomogram, and compared with the TNM staging systems on HCC. Internal validation was assessed. An independent validation cohort contained 150 continuous patients from 2014 to 2015. Independent factors for overall survival (OS) were body mass index (BMI), tumor stage, distant metastases, HBs Ag, lactate dehydrogenase (LDH), gamma-glutamyl transpeptidase (GGT), and albumin (ALB), which were all contained into the nomogram. The calibration curve for probability of OS showed good agreement between prediction by nomogram and actual observation. The C-index of nomogram was 0.807 (95% CI: 0.770-0.844), which was superior to the C-index of AJCC TNM Stage (0.697). The AUC was 0.809(95%CI: 0.762-0.857). In the validation cohort, the nomogram still gave good discrimination (C-index: 0.866, 95% CI: 00.796-0.936; AUC: 0.832, 95%CI: 0.747-0.917) and good calibration. Decision curve analysis demonstrated that the nomogram was clinically useful. Moreover, patients were divided into three distinct risk groups for OS by the nomogram: low risk group, middle risk group and a high risk group, respectively. The proposed nomogram presents more accurate and useful prognostic prediction for patients with AFP-negative HCC.