International multisociety Delphi consensus for liver tumour thermal ablation: margin assessment

This multisociety, multidisciplinary consensus-formally endorsed by the European Society of Surgical Oncology, the Cardiovascular and Interventional Radiological Society of Europe, and the Society of Interventional Oncology-was developed to standardise the assessment of ablation margins in liver tumour thermal ablation. A modified Delphi process, consisting of two online surveys and a hybrid (online and in-person meeting in Innsbruk) consensus meeting of 72 experts from North America, South America, Europe, and Asia. Formal consensus was reached for 150 (75%) of 199 statements. Strong agreement was observed between interventional and surgical oncologists, with only 12 (6%) of 199 statements showing significantly different ratings. Participants agreed that ablation margins should be assessed and documented for every treated tumour. Margins should be assessed quantitatively in three dimensions, with contrast-enhanced CT or MRI, preferably intraprocedurally with ablation confirmation software. Ablation margins should be categorised as A0 (tumour completely covered with sufficient margin), A1 (tumour completely covered but insufficient margin), or A2 (portion of tumour remains unablated). This effort is, to our knowledge, the first international consensus initiative to define best-practice recommendations for margin assessment in liver tumour thermal ablation to standardise practices, aiming to improve and promote uniform outcomes.