Synchronous CT-guided Brachytherapy in Patients at Risk for Incomplete Interstitial Laser Ablation of Liver Malignancies

Objectives: Indications for additional brachytherapy after CT guided interstitial laser ablation in patients with liver malignancies.Materials and methods: Fourteen patients with eighteen liver metastasis received high-dose-rate (HDR) brachytherapy directly following MR-guided interstitial laser ablation. Indications for additional brachytherapy were as follows: tumor size >5 cm, adjacent central bile duct or adjacent major vessels causing unfavourable cooling effects for thermal ablation, and technical failures of laser ablation. Dosimetry for brachytherapy was performed using three-dimensional CT data acquired after percutaneous applicator positioning for laser treatment. In average, a minimal dose of 17 Gy inside the tumor margin was applied (range: 10–20 Gy).Results: The mean tumor size was 4.3 cm (2.1–7.2 cm). The mean liver volume receiving ≥5 Gy was 16% of the liver total (2–40%). Severe complications were recorded in 1 patient. One patient developed acute liver failure possibly related to accidental continuation of oral capecitabine treatment (5 FU). Commonly encountered moderate increase of liver enzymes was observed. Local control rates after 9 months were 93% and after 12 month 86% for combined treatment with brachytherapy, respectively.Conclusion: CT guided brachytherapy using 3D CT data for dosimetry is safe and effective in combination with interstitial laser ablation. Brachytherapy as an additional treatment displayed sincere advantages over thermal ablation alone in critical location of the tumor.