CLINICAL LASER PHOTODYNAMIC THERAPY IN THE TREATMENT OF BLADDER CARCINOMA

Abstract

Abstract The treatment of bladder carcinoma using dihematoporphyrin ether (DHE) and laser photodynamic therapy (PDT) is described herein. Patients selected for this study have cytology‐ and biopsy‐proven transitional cell carcinoma, no histologic evidence of muscle invasion, and negative excretory urograms. Sixteen patients have been treated, with follow‐up from 6 to 36 months. Eleven have had a complete response, and 3 a partial response in that they required re‐treatment for recurrence. Two of these patients have not recurred at this time. One of the patients who recurred had tumor extension into the prostatic urethra and has been successfully re‐treated (disease‐free at 6 months). There was one treatment failure and 1 patient lost to follow‐up. Photosensitivity for up to 4 weeks is a known side‐effect, but unexpected morbidity included a transient but significant increase in urinary frequency, urgency, and occasionally hematuria which spontaneously resolved within 3‐4 weeks. Careful placement of the fiberoptic tip in the centre of the bladder, bladder distension during treatment with saline rather than water, the instillation of the minimum volume required to “smooth out” the mucosa for complete bladder photoradiation, and delivered energy of 25 J cm’or less may have prevented the more severe complications (i.e. bladder shrinkage) reported by Dougherty and Nseyo (personal communication). We also feel that there is some early evidence that a heightened immune response (similar to intravesical BCG) may potentially play some role in explaining the efficacy of PDT in long disease‐free intervals, although this is just a histologic observation at present. It appears the PDT offers another practical treatment modality for non‐invasive transitional cell carcinoma in patients refractory to standard surgical and chemotherapeutic regimens, and has been addressed by numerous other investigators such as Benson (1985) and Hisazumi (1983). We are presently recommending to our patients in these categories to undergo a course of PDT prior to relinquishing to cystectomy.