Table 2.

Definitions.

Term	Definition
Technical success	Ablation protocol completed and tumor covered (on immediately post-ablation CT)
Complete ablation(Technique effectiveness)	Ablation defect covering the entire tumor on the 4–6 week post- ablation CT
Local Tumor Progression	Evidence of tumor recurrence (progression) in the previously ablated area by CT criteria enlargement of the ablation size increase of enhancement and/or irregular and nodular increase of enhancement in the ablated zone
Primary LTP-free survival	Time period between the initial RF Ablation and the first radiologic evidence of LTP
Assisted LTP-free survival	Cumulative time interval between the first RF ablation and the latest radiologic follow-up showing evidence of LTP (local tumor recurrence); includes all the ablations performed for the treatment of the same target tumor to treat LTP
Overall Survival	Time period between the initial RF ablation and patient’s death from any cause, or most recent follow-up
Clinical Risk Score (CRS) modified for Ablation Patients with 0-2 points: low risk Patients with 3–4 points: high risk	One point for each: node-positive primary tumor disease-free interval from primary to liver metastases (DFI) <12 months number of hepatic tumors >1 any hepatic tumor >3 cm