Intrabiliary RF Heat-enhanced Local Chemotherapy of a Cholangiocarcinoma Cell Line: Monitoring with Dual-modality Imaging--preclinical Study

Purpose: To determine whether magnetic resonance (MR) imaging heating guidewire-mediated radiofrequency (RF) hyperthermia could enhance the therapeutic effect of gemcitabine and 5-fluorouracil (5-FU) in a cholangiocarcinoma cell line and local deposit doses of chemotherapeutic drugs in swine common bile duct (CBD) walls.

Materials And Methods: The animal protocol was approved by the institutional animal care and use committee. Green fluorescent protein-labeled human cholangiocarcinoma cells and cholangiocarcinomas in 24 mice were treated with (a) combination therapy with chemotherapy (gemcitabine and 5-FU) plus RF hyperthermia, (b) chemotherapy only, (c) RF hyperthermia only, or (d) phosphate-buffered saline. Cell proliferation was quantified, and tumor changes over time were monitored with 14.0-T MR imaging and optical imaging. To enable further validation of technical feasibility, intrabiliary local delivery of gemcitabine and 5-FU was performed by using a microporous balloon with (eight pigs) or without (eight pigs) RF hyperthermia. Chemotherapy deposit doses in the bile duct walls were quantified by means of high-pressure liquid chromatography. The nonparametric Mann-Whitney U test and the paired-sample Wilcoxon signed rank test were used for data analysis.

Results: Combination therapy induced lower mean levels of cell proliferation than chemotherapy only and RF hyperthermia only (0.39 ± 0.13 [standard deviation] vs 0.87 ± 0.10 and 1.03 ± 0.13, P < .001). Combination therapy resulted in smaller relative tumor volume than chemotherapy only and RF hyperthermia only (0.65 ± 0.03 vs 1.30 ± 0.021 and 1.37 ± 0.05, P = .001). Only in the combination therapy group did both MR imaging and optical imaging show substantial decreases in apparent diffusion coefficients and fluorescent signals in tumor masses immediately after the treatments. Chemotherapy quantification showed a higher average drug deposit dose in swine CBD walls with intrabiliary RF hyperthermia than without it (gemcitabine: 0.32 mg/g of tissue ± 0.033 vs 0.260 mg/g ± 0.030 and 5-FU: 0.660 mg/g ± 0.060 vs 0.52 mg/g ± 0.050, P < .05).

Conclusion: The use of intrabiliary MR imaging heating guidewire-mediated RF hyperthermia can enhance the chemotherapeutic effect on a human cholangiocarcinoma cell line and local drug deposition in swine CBD tissues.