INTERSTITIAL LASER COAGULATION OF THE PROSTATE - AN EXPERIMENTAL-STUDY

We describe a percutaneous, low power, interstitial method of controll ed coagulation of prostatic tissue by laser light which may prove an a lternative or adjunct to existing therapy for benign and malignant pro static disease. One or more 200-600 micron diameter fibres were implan ted within the substance of the elderly male beagle prostate (n = 11) through which Neodymium-Yttrium Aluminium Garnet (Nd-YAG) laser energy could be transmitted. Using longer exposures (400-1500s) and lower po wers (1-2W) than used in routine endoscopic laser therapy, well define d areas of coagulative necrosis could be created with little tissue ch arring or damage to the fibre. For an energy dose of 1000J a lesion ap proximately 1 cm in diameter resulted at 4 days. Ultrasound scanning m ethods could detect the fibre(s), the area(s) of coagulation and the h ealed lesions. Treatments were well tolerated. At 6 weeks the treated areas of canine prostate healed by fibrosis surrounding an area of cys tic degeneration. Multiple fibre experiments produced larger volume le sions relevant to more extensive cancer or to the coagulation of benig n adenomatous hyperplasia causing outflow symptoms. This technique may prove of value for the treatment of moderate benign enlargement of th e prostate and for the destruction of small, focal prostatic tumours.