Interstitial laser hyperthermia: a new approach to local destruction of tumours.

The use of local hyperthermia to treat cancer of the internal organs has been limited by the difficulty of controlling delivery of heat and limiting the effects to the tumour, but this can be overcome by using laser light transmitted through thin flexible fibres. Laser energy was delivered to tumours through fibres inserted percutaneously through needles directly into the centre of the tumour area. Ultrasound scanning was used to locate the tumour, position the fibres correctly within the tumour, and monitor the development of thermal necrosis in real time during laser exposure and through the subsequent period of healing. Five patients were treated (one with a tumour of the breast, one with a subcutaneous secondary tumour, one with a recurrent pancreatic tumour, and two with secondary tumours in the liver). Tumour necrosis was found on ultrasonography or computed tomography in all, and there were no immediate or delayed complications. In one patient the size of the isolated secondary tumour in the liver had not increased over 10 months, and he subsequently showed no other evidence of residual cancer. To develop this technique careful studies are essential to ensure that in every case the extent of thermal necrosis produced by absorption of the laser light can be matched to the full extent of the tumour being treated and that there is always sufficient adjacent normal tissue to ensure safe healing. These preliminary results suggest that this simple technique can be applied safely and effectively to common tumours in humans; more extensive trials in a range of cancers of solid organs are warranted.