Liver tumours and MR-guided laser ablation

20 December 2005
www.mtbeurope.info

Destruction of cancerous liver tissue by laser light guided by magnetic resonance (MR) imaging was found to be as effective as traditional surgery for some patients, in a large-scale, 12-year study in Germany.

In the largest study of its type with the longest follow-up, 839 patients at the University of Frankfurt in Germany received MR-guided laser-induced thermotherapy (LITT) for the treatment of liver tumours resulting from colorectal cancer. Between 1993 and 2005, the researchers treated 2,506 liver tumours and tracked survival rates to evaluate the long-term results of the procedure. The average survival rate from the date of diagnosis was 3.8 years, which compares favourably to survival rates after traditional surgery (approximately 1.5 to 5.0 years). The study was presented at the annual meeting of the Radiological Society of North America (RSNA).

In LITT, also known as laser ablation, laser light is used to destroy tumour tissue. According to the study’s lead author, Martin Mack, M.D., laser ablation has many advantages over other treatment methods.

“Traditional surgical resection has higher morbidity and mortality rates than laser ablation,” said Dr. Mack, an associate professor in the department of diagnostic and interventional radiology at the University of Frankfurt. “Laser treatment can be done on an outpatient basis under local anaesthesia. Typically, the patient stays only a couple of hours, instead of a couple of weeks in the hospital after surgical liver resection,” he said.

Laser ablation can be used to on tumours that occur in both halves of the liver — often during the same treatment — which is practically impossible in a traditional surgery where typically only the left or right lobe is resected. If new tumours are found during follow-up exams, it is much easier to repeat laser ablation than to subject the patient to another open surgery.

Laser ablation also holds advantages over radiofrequency ablation, another minimally invasive method of treating liver tumours, because it can be applied to different parts of the liver simultaneously and can be used with MR guidance to provide the radiologist with an accurate image of the tumour for precise targeting throughout the procedure. Radiofrequency ablation can only treat one tumour at a time and cannot be used with continuous MR monitoring.

Dr. Mack believes that laser combined with MR guidance will have wide-ranging impact on the treatment of tumours throughout the body, and may one day replace traditional surgery as the gold standard of treatment.

“Many surgeons are already performing local ablation instead of resection, because they have already recognized the positive effect of local ablation,” he said. “I believe that minimally invasive tumour ablation together with chemotherapy will play the most important role in the treatment of tumours in the years to come.”