An apparatus and method for determining a volume of tumor mass (40) destroyedwhich include a temperature probe (16) and a laser probe (14) having atemperature sensor (15). The laser probe (14) and temperature probe (16) areinserted to measure a temperature of the tumor mass (40) and a temperature oftissue mass (38) surrounding the tumor mass (40). By determining the volume oftumor mass (40) destroyed, a graphical representation monitoring of thedestruction of the tumor mass is achieved.