Are all local tumour progressions of HCC related to thermal ablation? A study of the causes and classification of local tumour progression.

• LTPs are not evenly distributed around the AZ. More than half of LTPs occur in the shortest AM quadrant. • Subgroup analysis showed that the occurrence of contacted-type LTPs (tumour margin has direct contact with the AZ) within 24 months after ablation indeed had a high proportion in the shortest AM quadrant, and they could be called ablation-related LTPs. • However, the dissociated-type LTPs (tumour margin adjacent to but not in contact with the AZ) or LTPs occurring beyond 24 months after ablation were evenly distributed around the AZ, and they could be called nonablation-related LTPs.