Laser ablation kills liver tumors

Contrast-enhanced MR image shows induced coagulation necrosis of a liver lesion immediately after LITT. (Provided by the RSNA)

MR-guided laser ablation proved as effective as the current standard of care for the treatment of liver tumors in a study by University of Frankfurt researchers. The trial highlights the largest patient population and longest follow-up of its kind.

Results from 839 patients followed during 12 years suggest that MR-guided laser-induced thermotherapy (LITT) offers several advantages over surgical resection, said principal investigator Dr. Martin Mack, an associate professor at Frankfurt's department of diagnostic and interventional radiology. He presented his findings at the 2005 RSNA meeting.

"Many surgeons are already performing local ablation instead of resection, because they have already recognized its positive effect," Mack said.

Mack and colleagues treated a total of 2506 liver tumors between 1993 and 2005, tracking patients' survival rates to evaluate the procedure's long-term effectiveness. They found that LITT's average survival rate of 3.8 years compared favorably with that of surgery, estimated at approximately 1.5 to five years.

One third of the lesions were 2 cm or less in diameter, one third were between 2 cm and 3 cm, 18% were between 3 cm and 4 cm, and 15% were larger than 4 cm.

Three-quarters of the patients had five liver metastases or less and no extrahepatic disease and were treated in curative intention. The rest were treated in palliative intention (patients with more than five metastases and/or limited extrahepatic disease).

Interventionalists can offer LITT on an outpatient basis under local anesthesia. Patients spend only a few hours instead of weeks in the hospital after surgical liver resection. Physicians can perform LITT simultaneously on both liver lobes and repeat treatment if they find new tumors at follow-up, which is virtually impossible by traditional surgical means, Mack said.

MR-guided laser ablation could become particularly appealing to patients. Researchers have found that resection has higher morbidity and mortality rates than laser ablation. LITT will have wide-ranging impact on the treatment of tumors throughout the body and may one day replace traditional surgery as the gold standard, according to Mack.

"I believe that minimally invasive tumor ablation together with chemotherapy will play the most important role in the treatment of tumors in the years to come," he said.

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