Failure of hepatocellular carcinoma surveillance: inadequate echogenic window and macronodular parenchyma as potential culprits

The purpose of this study was to examine the associations between ultrasonography (US) quality and clinical outcomes in patients undergoing surveillance for hepatocellular carcinoma. Between 2008 and 2013, 155 patients were diagnosed with liver cancer during regular surveillance by positive US results (US group, n=82) or by computed tomography (CT) or magnetic resonance image (MRI) scanning as alternative modalities (CT/MRI group, n=73). The quality of the echogenic window, macronodularity of the liver parenchyma, and occurrence of surveillance failure (initial tumor diagnosis beyond the Milan criteria or at Barcelona Clinic Liver Cancer stage B or C) were evaluated. Overall survival was compared according to whether surveillance failure occurred. The patients in the CT/MRI group with negative US results had a higher proportion of parenchymal macronodularity on US than those in the US group (79.5% vs. 63.4%, P=0.028). Surveillance failure tended to be more common in the US group than in the CT/MRI group (40.2% vs. 26.0% by the BCLC staging system [P=0.061]). In the US group, surveillance failure occurred more frequently when the echogenic window was inadequate (50.0% vs. 19.4% by the Milan criteria [P=0.046]). Significantly poorer 5-year overall survival was associated with surveillance failure (P≤0.001). Parenchymal macronodularity hindered the detection of early-stage tumors during US surveillance. Using an alternative imaging modality may help prevent surveillance failure in patients with macronodular parenchyma on US. Supplemental surveillance strategies than US may also be necessary when the echogenic window is inadequate.