A Nomogram Predicting Extrahepatic Metastases for Patients with Adjuvant Transarterial Chemoembolization after Hepatectomy

Background: Prognosis remains poor for hepatocellular carcinoma (HCC) patients with extrahepatic metastases (EHMs). This study aimed to develop a nomogram to predict EHMs in HCC patients who underwent adjuvant transarterial chemoembolization (TACE) following hepatectomy. Methods: Data of 578 HCC patients who underwent TACE after hepatectomy at the Eastern Hepatobiliary Surgery Hospital was retrospectively reviewed. Cox regression analyses was used to select variables to construct the nomogram. Predictive accuracy and discriminative ability of the model were performed using concordance index (C-index), calibration curve and the area under time-dependent receiver operating characteristic (ROC) curve. Results: Postoperative EHMs were detected in 89 and 31 patients in the training cohort (n = 453) and validation cohort (n = 125), respectively. Multivariate analysis showed that tumor size (HR, 1.099; 95% CI, 1.049-1.152), coarse beam type of tumor histopathological structure (HR, 2.382; 95% CI, 1.030-5.512), presence of satellite nodules (HR, 1.936; 95% CI, 1.156-3.244) and alpha-fetoprotein (AFP) (HR, 1.399; 95% CI, 1.098-1.783) were independent risk factors for EHMs (all p < 0.05). The nomogram incorporated these factors achieved good agreement between prediction and actual observation with a concordance index (C-index) of 0.73 (95% CI, 0.68 to 0.78) and 0.71 (95% CI, 0.63 to 0.79) in the training cohort and validation cohort, respectively. In addition, patients who had a nomogram score > 17 were considered to have higher risk for EHMs compared with those scored ≤ 12. Furthermore, the time-dependent area under the ROC curve indicated comparative stability and adequate discriminative ability of the model. Conclusions: This novel nomogram can identify those with high risk of EHMs after adjuvant TACE following hepatectomy. The validation cohort showed a good performance, suggesting it could benefit surgeons on decision-making.