Factors Associated with Local Tumor Control and Complications after Thermal Ablation of Colorectal Cancer Liver Metastases: a 15-year Retrospective Cohort Study

ABSTRACT Purpose To identify risk factors associated with local tumor progression-free survival (LTPFS) and complications after colorectal liver metastases (CLM) thermal ablation (TA). Methods This retrospective analysis included 286 patients with 415 CLMs undergoing TA (RFA, MWA) in 378 procedures from 1/2003 to 7/2017. Prior hepatic artery infusion (HAI), bevacizumab, pre-existing biliary dilatation, ablation modality, minimal ablation margin (MM), prior hepatectomy, CLM number and size were analyzed as factors influencing complications and LTPFS. Statistical analysis included Kaplan-Meier method, Cox proportional hazards model, competing risk analysis, univariate/multivariate logistic/exact logistic regressions and Fisher’s exact test. Complications were reported according to modified SIR guidelines. Results Median follow-up was 31 months. There was no LTP for MM >10mm. Smaller tumor size, increased MM and prior hepatectomy correlated with longer LTPFS. Major complication rate was 28/378 (7%). There were no biliary complications in HAI-naive patients, vs 11% in HAI patients (p 10mm. In HAI patients ablation with 6-10mm and >10mm MM resulted in major biliary complication rates of 4% and 21% (p=0.0011), with corresponding LTP rates of 24% and 0%, (p=0.0033). In HAI-naive patients LTP rates for 6-10mm and >10mm MM were 27% and 0%, respectively. Conclusions No LTP was seen for MM >10mm. Biliary complications occurred only in HAI patients, especially in those with biliary dilatation, bevacizumab and MM >10mm. In HAI patients MM of 6-10mm resulted in 76% local tumor control and 4% major biliary complications incidence.