Abstract No. 500 Cryoprobe factors associated with higher complication rates in patients undergoing percutaneous image-guided liver tumor cryoablation

Abstract

The goal of this study was to evaluate possible associations between cryoablation probe factors and high-grade adverse events (AE) in patients undergoing percutaneous image-guided hepatic tumor cryoablation. In this IRB-approved retrospective study, a total of 204 patients were studied. Inclusion criteria included (1) age>18 years, (2) pathology-proven hepatic malignancy, and (3) and image-guided hepatic cryoablation performed between October 1998 and December 2018. The standard cryoablation protocol utilized the SeedNet system (Galil Medical, Inc) and included two 15-minute freeze applications separated by a 10-minute thaw. Procedure-related AE were graded using the CTCAE grading system. High-grade postprocedural AE were defined as CTCAE grades 3 or higher. Chi-squared analysis and ANOVA analysis were used to assess for statistically significant differences for categorical variables and continuous variables, respectively. Univariate analysis was used to assess the clinical and technical factors associated with high-grade AE. Factors assessed included demographic data, tumor type, number of cryoablation probes used and probe insulation. A total of 204 patients met inclusion criteria (52% female, age range 29 to 91, mean 62.4). Average tumor diameter was 2.4 ± 1.1 cm (range, 0.4-5 cm). 25% of tumors were primary hepatic malignancies with the remaining consisting of metastatic hepatic lesions. Insulated probes were used in 50% of the cases. The mean number of probes used was 3.6 ± 2.7. We observed an overall 28% AE rate during the study period, the high-grade AE rate was 6%. There were a total of 22 grade 1, 24 grade 2, 8 grade 3 and 3 grade 4 AE. No grade 5 AE occurred. A higher number of cryoablation probes (OR = 1.42, P <0.001) and lack of probe insulation (OR = 5.1, P = 0.042) were associated with increased likelihood of high-grade AE. None of the other assessed factors were associated with high-grade AE. The use of insulated cryoablation probes and the use of fewer probes (when feasible) may reduce the likelihood of high-grade AE in patients undergoing hepatic cryoablation.