[Stereotactic Radiofrequency Ablation (SRFA) of intrahepatic cholangiocellular carcinomas: a minimal invasive alternative to liver resection]. / Stereotaktische Radiofrequenzablation von intrahepatischen cholangiozellulären Karzinomen - eine minimal invasive Alternative zur Leberresektion.

Up to now resection and liver transplantation are concerned as the only curative treatment options for intrahepatic cholangiocellular carcinomas (ICCs). For patients with inoperable ICCs systemic chemotherapy and various locoregional therapies including transarterial (chemo)embolization (TACE), selective internal radiation therapy (SIRT), radiofrequency ablation (RFA) and microwave ablation (MWA) are applied. Stereotactic RFA (SRFA) allows for precise 3D planning and positioning of multiple RF electrodes. Due to overlapping necroses tumors > 5 cm can be completely ablated in one session. 17 inoperable consecutive patients with 52 ICCs were treated with stereotactic RFA (SRFA). A median overall survival of 60 months was achieved. The two largest tumors with diameters > 10 cm were completely ablated. These SRFA data of irresectable ICCs are superior to the published data on resection. SRFA is a minimal invasive alternative treatment to resection and may be considered as the first-line local treatment of patients with ICCs in selected patients.

Percutaneous stereotactic radiofrequency ablation of colorectal liver metastases.

OBJECTIVES: To evaluate the outcome of patients with colorectal liver metastasis (CRLM) treated with stereotactic radiofrequency ablation (SRFA). METHODS: Following IRB approval, a retrospective evaluation of 98 SRFA treatment sessions of 189 CRLMs in 63 consecutive patients was performed. Local recurrence rate (LR), overall survival (OS) and disease-free survival (DFS) were analysed. RESULTS: LR was identified in 16% of the tumours (31/189), with no significant differences (P = 0.635) when comparing tumour sizes <3 cm (17.7%), 3-5 cm (11.1%) and >5 cm (17.4%). The median OS from SRFA treatment was 33.2 months after a mean follow-up of 25 months (range 2-66); the corresponding 1-, 3- and 5- year survival rates were 87%, 44% and 27%. The median OS was significantly different when comparing unresectable and resectable patients (27 vs. 58 months, P = 0.002) with OS rates of 92%, 66% and 48% at 1, 3 and 5 years in resectable patients. Tumour size did not affect OS and DFS. CONCLUSION: Due to the favourable outcome, SRFA challenges resection as first-line local treatment of patients with CRLM. As long as randomised studies are pending, we recommend entering an individual decision-making process with every patient. KEY POINTS: Large colorectal liver metastases can be effectively treated by stereotactic radiofrequency ablation (SRFA). Using SRFA the overall survival is not affected by tumour size. SRFA achieves similar overall and disease-free survival rates as surgical resection. SRFA challenges surgical resection as the first-line treatment for colorectal liver metastases.

Targeting accuracy of CT-guided stereotaxy for radiofrequency ablation of liver tumours.

The targeting accuracy during CT-guided stereotactic radiofrequency ablation (SRFA) of liver tumours was evaluated in a clinical study. Patients under general anaesthesia were immobilized using a vacuum cushion and respiratory motion control was based on temporary disconnections of the endotracheal tube. An optical-based navigation system was used for 3D trajectory planning and needle placement via a stereotactic aiming device. A control CT with the needles in place was fused with the planning CT for accuracy evaluation. Sub-analysis was performed for "location" (liver segments II-VIII), "approach" (intercostal or transabdominal), "properties" (clear parenchymal, subcapsular, subphrenic, fat, and subphrenic plus fat), and "path length". In 20 patients with 35 liver lesions, a total of 145 needles were placed with mean (±SD) lateral errors of 3.6 ± 2.5 mm at the needle tip, angular errors of 1.3° ± 1.2°, and longitudinal errors at the needle tip of -7.4 ± 6.2 mm. No puncture-related complications were noted. No significant differences of angular errors between segments, approach and properties were recorded. Long paths correlated with smaller angular errors. CT-guided stereotaxy can be considered safe and provided precise multiple needle placement for SRFA of liver lesions at arbitrary trajectories in various segments and locations.

Stereotactic radiofrequency ablation (SRFA) of liver lesions: technique effectiveness, safety, and interoperator performance.

PURPOSE: To evaluate technique effectiveness, safety, and interoperator performance of stereotactic radiofrequency ablation (SRFA) of liver lesions. METHODS: Retrospective review including 90 consecutive patients from January 2008 to January 2010 with 106 computed tomography-guided SRFA sessions using both single and multiple electrodes for the treatment of 177 lesions: 72 hepatocellular carcinoma (HCC) and 105 metastases with a mean size of 2.9 cm (range 0.5-11 cm). Technique effectiveness and 1-year local recurrence were evaluated by computed tomographic scans. Complications, mortality, and hospital days were recorded. The performance between an experienced and inexperienced interventional radiologist was compared. RESULTS: The overall technique effectiveness after a single SRFA was 95.5% (93.1% for HCC and 97.1% for metastases). Four of the eight unsuccessfully treated lesions could be retreated (secondary technique effectiveness of 97.7%). Local recurrence at 1 year was 2.9%. Technique effectiveness was significantly different for lesions<5 cm (96.7%) and >5 cm (87.5%) (P=0.044) but not for lesions<3 cm (95.9%) and 3-5 cm (100%). Compared to clear parenchymal property (97.3%), vessel vicinity (93.3%) (P=0.349) and subcapsular (95.2%) (P=0.532) had no, but hollow viscera vicinity (83.3%) had a significantly lower technique effectiveness (P=0.020). Mortality rate was 0.9%. Major complications and hospital days were higher for cirrhosis Child-Pugh B (20%, 7.2 days) than Child-Pugh A (3.1%, 4.7 days) patients and for metastases (5.1%, 4.3 days). There was no significant difference in interoperator performance. CONCLUSION: SRFA allowed for efficient, reliable, and safe ablation of large-volume liver disease.

Multipolar radiofrequency ablation using 4-6 applicators simultaneously: a study in the ex vivo bovine liver.

In this study the volume and shape of coagulation zones after multipolar radiofrequency ablation (RFA) with simultaneous use of 4-6 applicators in the ex vivo bovine liver were investigated. The RF-applicators were positioned in 13 different configurations to simulate ablation of large solitary tumors and simultaneous ablation of multiple lesions with 120 kJ of applied energy/session. In total, 110 coagulation zones were induced. Standardized measurements of the volume and shape of the coagulation zones were carried out on magnetic resonance images and statistically analyzed. The coagulation zones induced with solitary applicators and with 2 applicators were imperceptibly small and incomplete, respectively. At 20mm applicator distance, the total ablated volume was significantly larger if all applicators were arranged in a single group compared to placement in 2 distant applicator groups, each consisting of 3 applicators (p=.001). The mean total coagulated volume ranged from immeasurably small (if 6 solitary applicators were applied simultaneously) to 74.7 cc (if 6 applicators at 30 mm distance between neighboring applicators were combined to a single group). Applicator distance, number and positioning array impacted time and shape. The coagulation zones surrounding groups with 4-6 applicators were regularly shaped, homogeneous and completely fused, and the axial diameters were almost constant. In conclusion, multipolar RFA with 4-6 applicators is feasible. The multipolar simultaneous mode should be applied for large and solitary lesions only, small and multiple tumors should be ablated consecutively in standard multipolar mode with up to 3 applicators.

Stereotactic radiofrequency ablation of unresectable intrahepatic cholangiocarcinomas: a retrospective study.

PURPOSE: To evaluate treatment effects, complications, and outcome of percutaneous stereotactic radiofrequency ablation (SRFA) of intrahepatic cholangiocarcinoma (ICC). PATIENTS AND METHODS: Eleven consecutive patients (nine men and two women) with a total of 36 inoperable ICCs (18 initial lesions, 16 lesions newly detected during follow-up, and two local recurrences) underwent SRFA between December 2004 and June 2010. Two different radiofrequency ablation (RFA) devices with internally cooled electrodes were used. Tumor diameters ranged from 0.5 to 10 cm (median 3.0 cm). A total of 23 SRFA sessions were performed. The efficacy of SRFA was evaluated by contrast-enhanced computed tomography or magnetic resonance imaging 1 month after treatment and then every 3 months. RESULTS: Primary technical effectiveness rate was 92%. Further follow-up every 3 months revealed three local recurrences (8%), two of which were successfully retreated, resulting in a secondary technical effectiveness rate of 98%. After a total of 23 RFA sessions, three major complications occurred (13%) that could be managed interventionally. Mean follow-up time was 35 months (range 12-81 months). One- and 3-year overall survival rates were 91 and 71%, respectively. The median overall survival was 60 months (according to the life table method). Eight (73%) of 11 patients were still alive at the end of follow-up. CONCLUSION: SRFA is effective in the treatment of unresectable ICC even if the tumor is large and located close to major vessels. SRFA shows a survival benefit compared to other palliative treatment options and may also be considered as the first-line local treatment of ICCs in selected patients.

Stereotactic radiofrequency ablation.

PURPOSE: To describe the technique of percutaneous stereotactic radiofrequency ablation (SRFA) and its application in a patient with an unresectable multifocal intrahepatic cholangiocarcinoma (ICC). MATERIALS AND METHODS: A 72-year-old man presented with two nodules of an ICC with a maximum diameter of 10 and 4 cm, respectively. To produce overlapping ablation areas and cover the entire tumor volume, 18 paths for the placement of radiofrequency ablation (RFA) probes at multiple locations were planned on 2D and 3D reconstructions of the computed tomographic (CT) data. The 15-gauge coaxial needles were advanced through the aiming device to the preplanned depth. A control CT fused to the planning CT data confirmed correct needle placements. RFA was performed with an impedance-based multiple-electrode RFA system. Fusion of the contrast-enhanced control CT with the planning CT showed an appropriate zone of ablation. RESULTS: Besides a mild asymptomatic pleural effusion, no complications occurred. Twenty-seven months after the first RFA, two new small distant liver metastases were successfully treated by SRFA. Currently, 38 months after diagnosis and 36 months after the first SRFA, the patient is free of detectable disease. CONCLUSION: SRFA seems to offer an effective treatment option in selected patients with even unresectable ICC.

Respiratory motion control for stereotactic and robotic liver interventions.

BACKGROUND: Control of respiratory motion is an essential prerequisite for stereotactic computer-assisted and robotic interventions in the liver. METHODS: The respiratory motion control error (RMCE) of temporary disconnections of the endotracheal tube (ETT) in anaesthetized patients has been evaluated during computer tomography (CT)-guided liver punctures. Two arterial and portal phase contrast-enhanced planning CTs were obtained during one ETT disconnection. After liver puncture, a native control CT was performed during a second ETT disconnection. By image fusion, the Euclidean errors of corresponding external and internal targets were calculated as baseline measures. RMCE was obtained by subtracting the Euclidean error during one ETT disconnection from the Euclidean error during two ETT disconnections. RESULTS: In 26 patients, the overall mean RMCE showed 1.98 +/- 0.93 (range 0.44-4.02) mm for external targets and 1.41 +/- 0.75 (range 0.46-3.18) mm for the internal targets, without significant difference in means (p = 0.558). No complications were noted. CONCLUSIONS: Temporary ETT disconnections are safe and may control respiratory motion for liver interventions within 4 mm.