Combined hepatocellular-cholangiocarcinoma: can we use contrast-enhanced ultrasound Liver Imaging Reporting and Data System (LI-RADS) to predict the patient's survival?

Objectives: To evaluate the relationship between contrast-enhanced (CE) ultrasound Liver Reporting and Data System (LI-RADS) classification of combined hepatocellular-cholangiocarcinoma (cHCC-CCA) and their histopathological component predominance, and to determine if the CEUS LI-RADS category can be used to predict the patient's survival after surgical resection.

Methods: Between January 2011 and December 2018, medical records and CEUS of patients with pathologically proven cHCC-CCA were studied. The predominance of hepatocellular carcinoma (HCC)/intrahepatic cholangiocarcinoma (ICC) component of cHCC-CCA was analyzed by histopathology. The proportion of HCC-predominant cHCC-CCA in different LI-RADS category was compared by using Fisher's exact test. Factors affecting tumor recurrence were analyzed by Cox proportional hazard model. Disease-free survival (DFS) was estimated by using Kaplan-Meier survival curve and compared by log-rank test.

Results: The study included 37 cHCC-CCA patients (33 men, 4 women; average age, 50.4 ± 11.0 years) and 37 nodules (mean diameter, 6.1 ± 3.9 cm). According to CEUS LI-RADS, 62.2% (23/37), 18.9% (7/37), and 18.9% (7/37) of cHCC-CCA were classified as LR-M, LR-5, and LR-TIV, respectively. The ratio of HCC predominance in LR-5 was 100% (10/10) vs 81.5% (22/27) in the LR-M group (p = 0.591). In our population, LR-5 patients had longer DFS than LR-M and LR-TIV patients combined (median DFS: 18.0 vs 6.4 months, p = 0.016). Multiple lesions (hazard ratio, 3.1; p = 0.007), tumor size (≥ 5 cm, hazard ratio, 4.1; p = 0.003), and CEUS LI-RADS category (LR-M and LR-TIV, hazard ratio, 4.7; p = 0.011) showed independent association with shorter DFS.

Conclusion: cHCC-CCA characterized as LR-5 on CEUS tend to represent HCC-predominant tumors with significantly longer disease-free survival compared to cHCC-CCA categorized as LR-M and LR-TIV.

Key points: • By using the American College of Radiology contrast-enhanced ultrasound Liver Imaging Reporting and Data System (CEUS LI-RADS), majority (30/37, 81.1%) of cHCC-CCA tumors were classified as LR-M or LR-TIV and only 18.9% (7/30) of cHCC-CCA were categorized as LR-5. • Patients with CEUS LR-5 cHCC-CCA had statistically significant longer disease-free time than those with LR-M and TIV cHCC-CCA (median DFS: 18.0 vs 6.4 months, p = 0.016). • Multiple lesions (hazard ratio, 3.1; p = 0.007), tumor size (≥ 5 cm, hazard ratio, 4.1; p = 0.003), and CEUS LI-RADS category (LR-M and LR-TIV, hazard ratio, 4.7; p = 0.011) showed independent association with shorter DFS.