Comparison between interstitial laser thermotherapy and excision of an adenocarcinoma transplanted into rat liver

The aim of this study was to compare interstitial laser thermotherapy with excision of a liver tumour. A dimethylhydrazine-induced adenocarcinoma was transplanted (implanted if not stated otherwise) into the left lateral lobe of the rat liver, and treatment was performed 8 days later. In the main ex periment, rats were treated with resection of the tumour-hearing lobe or un derwent interstitial laser thermotherapy, which was performed at a steady-s tate temperature of 46 degrees C for 30 min, 3 mm from the tumour margin. T he incidence and extent of intraperitoneal spread was smaller after laser t hermotherapy than after resection of the tumour-bearing robe, with no diffe rence in local control. Metastatic spread after resection of the median liv er lobe was similar to that observed after sham procedures for thermotherap y or resection, suggesting that the advantage of thermotherapy was not due to a difference in surgical trauma. Additional studies showed that laser th ermotherapy reduced intraperitoneal spread when treatment was suboptimal or in a tumour inoculation model and suggested that immunological mechanisms might be involved. It is concluded that interstitial laser thermotherapy re duces spread of liver tumour compared with resection.