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 °C to 20 °C at the tip and 0 ° to 8 °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.