Multi-institutional development and external validation of a nomogram for prediction of extrahepatic recurrence after curative-intent resection for hepatocellular carcinoma

Backgrounds: Extrahepatic recurrence of hepatocellular carcinoma (HCC) after surgical resection is associated with unfavorable prognosis. The objectives of the current study were to identify the risk factors and develop a nomogram for the prediction of extrahepatic recurrence after initial curative surgery. Methods: A total of 635 patients who underwent curative-intent resection for HCC between 2000 and 2017 were identified from an international multi-institutional database. The clinicopathological characteristics, risk factors, and long-term survival of patients with extrahepatic recurrence were analyzed. A nomogram for the prediction of extrahepatic recurrence was established and validated in 144 patients from an external cohort. Results: Among the 635 patients in the derivative cohort, 283 (44.6%) experienced recurrence. Among patients who recurred, 80 (28.3%) patients had extrahepatic ± intrahepatic recurrence, whereas 203 (71.7%) had intrahepatic recurrence only. Extrahepatic recurrence was associated with more advanced initial tumor characteristics, early recurrence, and worse prognosis versus non-extrahepatic recurrence. A nomogram for the prediction of extrahepatic recurrence was developed using the β-coefficients from the identified risk factors, including neutrophil-to-lymphocyte ratio, multiple lesions, tumor size, and microvascular invasion. The nomogram demonstrated good ability to predict extrahepatic recurrence (c-index: training cohort 0.786; validation cohort: 0.845). The calibration plots demonstrated good agreement between estimated and observed extrahepatic recurrence (p = 0.658). Conclusions: An externally validated nomogram was developed with good accuracy to predict extrahepatic recurrence following curative-intent resection of HCC. This nomogram may help identify patients at high risk of extrahepatic recurrence and guide surveillance protocols as well as adjuvant treatments.