Laser Therapy Offers Alternative to Surgery for Liver Tumours

Research News in the British Journal of Surgery

11 September 2003: Laser light can be delivered in a controlled and predictable manner to destroy tumours. By inserting fibre optic cables through needles, doctors can direct the powerful laser light onto liver tumours – killing the cells and thus eliminating the need for major surgery. A review of recent research shows that this ‘interstitial laser thermotherapy’ (ITL) can be a safe and effective way of removing tumours and improving overall survival.

Cancer in the liver is extremely serious; left untreated, it can kill a person within three to twelve months of diagnosis. The best way of treating this disease is to remove the tumour by conventional surgery, but this is a major operation and is only possible in a limited number of cases.

“ITL allows a greater proportion of patients to be treated than surgery alone, but we need greater understanding of how it works if we are going to make best use of the technology,” says lead-author, M Nikfarjam, who works in the department of Surgery, at the University of Melbourne in Australia. “Advances in laser technology and refinements in techniques may allow ILT to replace surgery as the procedure of choice in selected patients with liver malignancies.”

Technical background

Lasers kill tumours because the energy contained in light particles (photons) is transformed into heat inside the cells. Heating cells to 42-45 oC for 30-60 minutes disrupts vital parts of the cells machinery (enzymes), killing the cells. Increasing the temperature decreases the amount of time needed. With temperatures of between 60oC and 140oC, cell death is almost instantaneous. Between 100 and 300 oC water in the cell vaporises, and above 300 oC the cells are burnt to carbon.

The key to success is to raise the temperature high enough to kill cells quickly, but to avoid carbonisation of the cells. If carbonisation occurs at the tip of the fibre, light is unable to penetrate the tissue. Doctors use either ultrasound scanning or magnetic resonance imaging to visualise the tumour and the fibres while they are giving the treatment.

Current research is focused on determining the optimum equipment and protocol to maximise the killing power of the laser.