Journal articles address complications; new ablation technologies

Journal articles this month review complications and side effects brought on by radiofrequency ablation and other tumor ablation techniques and profile new technologies for tumor ablation procedures.

Complications and side effects

Adverse effects of radiofrequency ablation of liver tumours in the Netherlands

Br J Surg 2005 Oct;92(10):1248-1254

A team from the Netherlands evaluated the complication rates encountered in 122 patients after treatment of 143 liver tumors with RFA between June 1999 and November 2003. Death occurred in two cases. In both, RFA was combined with partial hepatectomy. The team found 19 major complications, including biliary tract damage, liver failure, hepatic abscess, peritoneal infection, intrahepatic hematoma, hepatic artery aneurysm, and pulmonary embolism and 24 minor complications related to concomitant partial hepatectomy or laparotomy. The overall complication rate was 20.3%, and the rate of complications related directly to RFA was 9.8%. The team recommended that RFA be performed only by an experienced team comprising a hepatobiliary surgeon, gastroenterologist, hepatologist, and interventional radiologist.

Radiofrequency ablation of liver tumors: a new cause of benign portal venous gas

Radiology 2005;237:709-717

A Boston-based study retrospectively described and categorized the presence of portal venous gas (PVG) from RFA of hepatic tumors, following 34 CT-guided percutaneous ablations of liver tumors in 26 patients. The team looked at both RFA alone and combined RFA and ethanol injection. The two ablation methods were compared for quantities of PVG and tumoral gas. The role of N2O anesthetic in PVG and tumoral gas formation during ablation also was studied. In 74% of cases, gas was found in portal vein branches. In 88%, gas was also found in tumoral and peritumoral tissues. The researchers found no significant difference in frequency of PVG between the ablation methods, but combined RF and ethanol ablation was associated with more PVG than was RF ablation alone.

Complications of percutaneous radiofrequency ablation for hepato-cellular carcinoma: imaging spectrum and management

RadioGraphics 2005;25:S57-S68

A Japanese team detailed the types of complications found over five years of experience performing RFA for the treatment of unresectable hepatocellular carcinoma. Complications are classified in three groups: vascular (e.g., portal vein thrombosis, hepatic vein thrombosis with partial hepatic congestion, hepatic infarction, and subcapsular hematoma), biliary (e.g., bile duct stenosis and biloma, abscess, and hemobilia), and extrahepatic (e.g., injury to the gastrointestinal tract, injury to the gallbladder, pneumothorax and hemothorax, and tumor seeding). The team concluded that most complications can be managed with conservative treatment, percutaneous or endoscopic drainage, or surgical repair.

New techniques

Microwave ablation: principles and applications

RadioGraphics 2005;25:S69-S83

Drs. Caroline J. Simon, Damian E. Dupuy, and William W. Mayo-Smith described developments in microwave ablation of tumors. They summarized the technique and equipment used with the procedure and identified the main advantages of microwave technology: consistently higher intratumoral temperatures, larger tumor ablation volumes, faster ablation times, and an improved convection profile. They suggested microwave ablation is a promising technology for the treatment of primary and secondary liver disease, primary and secondary lung malignancies, renal and adrenal tumors, and bone metastases.

Feasibility of US-guided high-intensity focused ultrasound treatment in patients with advanced pancreatic cancer: initial experience

Radiology 2005;236:1034-1040

A Chinese study evaluated sonographically guided high-intensity focused ultrasound in the treatment of patients with advanced-stage pancreatic cancer. The team followed eight patients who underwent high-intensity focused ultrasound ablation and noted changes in symptoms and survival time. No complications were observed, and preexisting severe back pain disappeared after intervention. Follow-up images revealed an absence of tumor blood supply and shrinkage of the ablated tumor. Four patients died, and four patients were alive at the time of this writing, with a median survival time of 11.25 months. The authors concluded that high-intensity focused ultrasound ablation is safe and feasible in the treatment of advanced pancreatic cancer.