Factors Associated With Local Tumor Control and Complications After Thermal Ablation of Colorectal Cancer Liver Metastases: A 15-year Retrospective Cohort Study

Thermal ablation of colorectal cancer liver metastases with minimum margin > 10 mm offers the best local tumor control. Biliary complications occurred only in patients that received hepatic artery infusion especially in the face of pre-existing biliary dilatation, exposure to bevacizumab, and ablation with minimum margin > 10 mm. For patients at risk, such as those in the hepatic artery infusion group, a margin of 6 to 10 mm offers 76% local tumor control rate and 4% major biliary complications incidence. Introduction: The purpose of this study was to identify risk factors associated with local tumor progression-free survival (LTPFS) and complications after colorectal liver metastases (CLM) thermal ablation (TA). Patients and Methods: This retrospective analysis included 286 patients with 415 CLM undergoing TA (radiofrequency and microwave ablation) in 378 procedures from January 2003 to July 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 the Kaplan-Meier method, Cox proportional hazards model, competing risk analysis, univariate/multivariate logistic/exact logistic regressions, and the Fisher exact test. Complications were reported according to modified Society of Interventional Radiology guidelines. Results: The median follow-up was 31 months. There was no LTP for MM > 10 mm. Smaller tumor size, increased MM, and prior hepatectomy correlated with longer LTPFS. The major complications occurred following 28 (7%) of 378 procedures. There were no biliary complications in HAI-naive patients, versus 11% in HAI patients (P <.001), of which 7% were major. Biliary complications predictors in HAI patients included biliary dilatation, bevacizumab, and MM > 10 mm. In HAI patients, ablation with 6 to 10 mm and > 10 mm MM resulted in major biliary complication rates of 4% and 21% (P = .0011), with corresponding LTP rates of 24% and 0% (P = .0033). In HAI-naive patients, the LTP rates for 6 to 10 mm and > 10 mm MM were 27% and 0%, respectively. Conclusions: No LTP was seen for MM > 10 mm. Biliary complications occurred only in HAI patients, especially in those with biliary dilatation, bevacizumab, and MM > 10 mm. In HAI patients, MM of 6 to 10 mm resulted in 76% local tumor control and 4% major biliary complications incidence. (C) 2020 Published by Elsevier Inc.

Automated summary

Thermal ablation with a minimum margin > 10 mm is effective for local tumor control in colorectal cancer liver metastases. However, it may lead to biliary complications. For patients at risk, a margin of 6 to 10 mm provides good control rate and reduces the incidence of biliary complications. The study found that biliary complications are more likely to occur in patients who received hepatic artery infusion, had biliary dilatation, and had a margin > 10 mm.