Effect of hepatocellular carcinoma conspicuity on ultrasound on the treatment outcome of percutaneous tumor ablation

Background: Percutaneous tumor ablation is a minimally invasive treatment for early-stage hepatocellular carcinoma (HCC) and relies on real-time ultrasonographic guidance. However, it might not be feasible in some patients due to limitations of grey-scale ultrasound findings. Objective: To evaluate the effect of ultrasound conspicuity of HCC nodules on the success rate of percutaneous image-guided ablation Materials and methods: A single-center retrospective review of patients undergoing percutaneous tumor ablation of treatment-naïve HCC from January 2017 to December 2022 was performed. Three groups of tumors were classified based on the level of ultrasound visualization as complete visibility (399 lesions), partial visibility (219 lesions) and invisibility (88 lesions). Ablation procedure was performed under ultrasound guidance, supplemented with other modalities such as non-contrast CT and fusion ultrasound. Follow-up assessments were conducted at 1, 3, and 24 months post-ablation to compare the technical success rates. Other outcomes including survival analysis and complications were also investigated. Results: A total of 447 patients with 706 lesions were included. The mean size of lesions in the three groups were 1.84, 1.59, and 1.11 cm, respectively, with statistically significant difference between the groups (p<0.001). There was no statistically significant difference in technical success rates at 1 month or primary efficacy at 3 months among the three groups. The technical success rate between the complete visibility, partial visibility, and invisible groups were 95.7%, 95.0%, and 97.7% (p=0.862), respectively and primary efficacy rates were 95.2%, 95.0%, 84.1% (p=0.172), respectively. The cumulative local tumor progression-free survival at 6, 12, 24 months were 98.0%, 96.9%, and 90.5% for the complete visibility group, 98.9%, 97.9%, and 87.8% for the partial visibility group, and 96.2%, 94.5%, and 87.3% for the invisible group, respectively, with no statistically significant differences (p = 0.539). Only one patient experienced a complication that required further treatment. Conclusion: The usage of other imaging modalities such as non-contrast CT and fusion ultrasound for poorly conspicuous HCC lesions can improve the success rates to levels comparable with those of the conspicuous nodules, while also maintaining similar local tumor control outcomes and avoiding major adverse events.