Extrahepatic Disease in Hepatocellular Carcinoma: Do We Always Need Whole-Body CT or Is Liver MRI Sufficient? A Subanalysis of the SORAMIC Trial

Abstract

Background: To investigate whole-body contrast-enhanced CT and hepatobiliary contrast liver MRI for the detection of extrahepatic disease (EHD) in hepatocellular carcinoma (HCC) and to quantify the impact of EHD on therapy decision. Methods: In this post-hoc analysis of the prospective phase II open-label, multicenter, randomized controlled SORAMIC trial, two blinded readers independently analyzed the whole-body contrast-enhanced CT and gadoxetic acid-enhanced liver MRI data sets of 538 HCC patients. EHD (defined as tumor manifestation outside the liver) detection rates of the two imaging modalities were compared using multiparametric statistical tests. In addition, the most appropriate treatment recommendation was determined by a truth panel. Results: EHD was detected significantly more frequently in patients with portal vein infiltration (21% vs. 10%, p < 0.001), macrovascular infiltration (22% vs. 9%, p < 0.001), and bilobar liver involvement (18% vs. 9%, p = 0.006). Further on, the maximum lesion diameter in patients with EHD was significantly higher (8.2 cm vs. 5.8 cm, p = 0.002). CT detected EHD in significantly more patients compared to MRI in both reader groups (p < 0.001). Higher detection rates of EHD in CT led to a change in management only in one patient since EHD was predominantly present in patients with locally advanced HCC, in whom palliative treatment is the standard of care. Conclusions: Whole-body contrast-enhanced CT shows significantly higher EHD detection rates compared to hepatobiliary contrast liver MRI. However, the higher detection rate did not yield a significant impact on patient management in advanced HCC.

Keywords: extrahepatic disease; hepatocellular carcinoma; liver MRI; patient management; therapeutic decision-making.

Figure 1

EHD leading to change in management in a patient with solitary HCC. (A): liver MRI, arterial phase and axial plane. (B): liver MRI, venous/transitional phase and axial plane. (C): liver MRI, hepatobiliary phase, and axial plane. (D): chest CT, lung window and axial plane. Note the solitary, typical HCC in liver segment VIII ((A–C), solid arrows) demonstrating arterial hypervascularization (A), venous/transitional phase washout (B), and hypointensity in the hepatobiliary phase ((C)—note is also made of visually reduced parenchymal contrast uptake due to impaired liver function). Based on hepatic disease, the treatment recommendation of RG1 was curative locoregional therapy. However, contrast-enhanced CT (D) revealed four pulmonary metastases in the right lung ((D), dashed arrows). The treatment recommendation was consequently changed to palliative systemic therapy.

Figure 2

No change in management despite CT-detected EHD. (A): liver MRI, arterial phase, and axial plane. (B): liver MRI, venous/transitional phase, and axial plane. (C): liver MRI, hepatobiliary phase, and axial plane. (D,E): chest CT, lung window, and axial plane. Note the solitary, typical HCC in liver segment III ((A–C), solid arrows) demonstrating arterial hypervascularization (A), portalvenous phase washout (B), and hypointensity in the hepatobiliary phase (C). CT showed two additional pulmonary metastases in the right lung ((D,E), dashed arrows). However, EHD did not lead to a change of the therapy recommendation, as palliative treatment was already recommended due to close proximity of the primary tumor to central vascular structures.

Figure 3

No change in management as EHD is present in both MRI and CT. (A,B): liver MRI, hepatobiliary phase, and axial plane. (C,D): abdomen and chest CT, soft tissue window, axial plane. Both MRI (A,B) and CT (C,D) show the HCC in liver segment II (solid arrows) and a cardiophrenic lymph node metastasis (dashed arrows). Therefore, palliative treatment was recommended, and additional CT staging did not result in a change in patient management. Paracentesis was performed between CT and MRI.