Hepatocellular carcinoma (HCC), the most common primary liver cancer, is a leading cause of cancer-related death worldwide. Local and locoregional therapies such as thermal ablation, transarterial chemoembolisation (TACE), radioembolisation (TARE) and stereotactic body radiation therapy (SBRT) offer curative or disease-controlling options, especially for patients unsuitable for surgery. Imaging plays a vital role throughout these treatments—for diagnosis, staging, planning, guidance and follow-up. However, imaging approaches vary widely across centres. In response, the European Organisation for Research and Treatment of Cancer (EORTC) and the European Society of Gastrointestinal and Abdominal Radiology (ESGAR) conducted a consensus study using the Delphi method to standardise periinterventional imaging in HCC care.
Harmonising Imaging Practices
The consensus survey involved 51 experts across 15 countries, reflecting a multidisciplinary spectrum including radiologists, oncologists and surgeons. Most participants performed over 40 ablation or TACE procedures annually, indicating high experience. There was clear agreement that pretreatment imaging should include both CT and MRI for optimal assessment of liver disease burden. Gadoxetic acid-enhanced MRI, diffusion-weighted imaging (DWI) and triphasic CT (arterial, portal and venous phases) were recommended as standard protocols. Thoracic CT was also considered essential, while PET-CT was not routinely recommended due to low sensitivity in HCC. Repeated imaging was advised if liver scans were older than one month or thoracic scans older than three months before treatment.
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Standardisation was also reached on the use of the Liver Imaging Reporting and Data System (LI-RADS) for HCC diagnosis. Biopsies were deemed unnecessary for typical lesions in at-risk patients, although recommended for ambiguous cases or when no histological confirmation existed. Lesions appearing hypointense on hepatobiliary phase imaging warranted particular attention, with most experts advocating for biopsy if they exceeded 1 cm in size.
Follow-Up Imaging Protocols
Post-treatment imaging is crucial for evaluating therapeutic response and guiding further interventions. For thermal ablation, although consensus on the exact timing of the first follow-up scan was not achieved, most participants agreed on repeating imaging every three months, preferably using MRI. Similarly, after TACE, imaging within one month was recommended, with continued tri-monthly monitoring. While MRI was generally preferred, no agreement was reached on its exclusive use, especially after lipiodol-based procedures, where CT may provide additional diagnostic value due to lipiodol retention patterns.
TARE and SBRT follow-up protocols were more clearly defined. Consensus indicated that the first post-TARE and post-SBRT imaging should be conducted in the third month following treatment. MRI was again the favoured modality, and imaging should be performed every three months thereafter. These recommendations aim to detect residual disease, recurrence and complications early enough to allow timely intervention.
Response assessment was guided by perfusion-based criteria. The modified Response Evaluation Criteria in Solid Tumours (mRECIST) was the most commonly used, but LI-RADS and EASL criteria were also accepted. While these systems differ slightly, they all emphasise enhancement patterns and vascularity, which are crucial for assessing viable tumour tissue in HCC.
Intraoperative and Technological Considerations
In terms of imaging during procedures, flexibility based on institutional experience was encouraged. Ultrasound, CT, MRI or fusion imaging could be used during thermal ablation, provided optimal lesion visibility was ensured. CT or MRI were both considered suitable for SBRT planning. Notably, cone beam CT was strongly recommended during TACE and TARE to identify vascular supply and improve targeting accuracy. Lipiodol TACE prior to thermal ablation was endorsed by many experts for enhancing lesion visibility during image-guided procedures.
While artificial intelligence is increasingly discussed in medical imaging, its role in HCC management remains limited. The consensus clearly indicated that AI is not yet established for either treatment decision-making or post-treatment follow-up in the context of locoregional therapies. This reflects the lack of robust evidence and randomised controlled trials in this area. Further studies will be necessary to define AI’s clinical value in HCC care.
The consensus recommendations from EORTC and ESGAR represent a significant step towards harmonising imaging practices for local and locoregional therapies in HCC. By defining standard protocols for staging, treatment planning, procedural guidance and follow-up, the guidelines aim to reduce variability and enhance care consistency across Europe. While some areas still lack consensus, particularly regarding imaging intervals and modality preferences in certain settings, the overall framework offers a robust foundation for clinical practice and future research. As new treatment combinations and technologies emerge, these standards will likely evolve, but this initiative marks a critical milestone in aligning imaging with therapeutic strategies in HCC management.
Source: European Radiology
Image Credit: iStock
