Overcoming the heat-sink phenomenon: successful radiofrequency thermal ablation of liver tumors in contact with blood vessels.
OBJECTIVE
To evaluate the efficacy and safety of computed tomography (CT)-guided radiofrequency thermal ablation (RFA) of liver tumors (hepatocellular carcinoma and liver metastases) > 3 mm in diameter that were in contact with blood vessels.


METHODS
During a 3-year period RFA was performed in 28 patients (age range, 36-83 years; male/female ratio, 17:11) with liver tumors (primary and metastatic) that were in contact with blood vessels > 3 mm in diameter. Tumor diameter ranged from 1.7 to 5.1 cm. To evaluate the immediate response, dual-phase dynamic CT images were obtained after intravenous contrast material administration. Imaging follow-up was at 1, 3, 6, and 12 months post-RFA, and every year thereafter.


RESULTS
All of 28 patients were treated with a total of 36 sessions. In 22 (79%) of the patients, complete ablation of the tumor was achieved. The remaining 6 (21%) patients showed irregular peripheral enhancement and underwent a second session. At 1-year follow-up 2 of the tumors showed a recurrent lesion and a new ablation was performed. The local tumor progression rate at 1-year follow-up was 8.7% and disease-free survival was achieved in 82.1% of the patients. Complications occurred in 4 patients (14.3%); 2 patients presented with a small sub-capsular hematoma, and 2 patients had a partial liver infarction.


CONCLUSIONS
RFA is a safe and effective method, even with high-risk tumors adjacent to large blood vessels, which can lead to good results with minimal complications and a low rate of tumor progression.
Thanos
Loukas
L
Department of Radiology, Sotiria Hospital, Athens, Greece. loutharad@yahoo.com
Mylona
Sophia
S
Galani
Panagiota
P
Pomoni
Maria
M
Pomoni
Anastasia
A
Koskinas
Ioannis
I
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D006528:Carcinoma, Hepatocellular / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D017115:Catheter Ablation / Q000009:adverse effects / Q000379:methods*; D006503:Hepatic Veins / Q000000981:diagnostic imaging; D006801:Humans; D008113:Liver Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D008875:Middle Aged; D009362:Neoplasm Metastasis; D011169:Portal Vein / Q000000981:diagnostic imaging; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D014421:Turkey; D014682:Vena Cava, Inferior / Q000000981:diagnostic imaging