Interstitial applications of laser irradiation in hematoporphyrin derivative-photosensitized Dunning R3327 prostate cancers.

Two prostate tumour models (Dunning R3327H and AT) were tested in rats to see if they were sensitive to hematoporphyrin-photoradiation therapy (HPD-PRT). The R3327H tumours were irradiated by implantation of a single fiber optic and the R3327 AT tumours were treated with implantation of four fiber optics simultaneously. Thermal measurements made at the tip of the fiber and up to 1 cm from the tip indicated temperature rises from 1.5 degree C to 20 degrees C at the tip and 0 degree to 8 degrees C distal to the tip, with power densities ranging from 100 mW to 500 mW. The R3327H tumour was controlled up to 8 weeks post-HPD-PRT, when the initial tumour size was 400-500 mm3. The R3327 AT tumours also respond to the HPD-PRT but a significant laser-induced thermal rise in the tumour is suspected.