DEVELOPMENT OF AN ALTERNATIVE LIGHT-SOURCE TO LASERS FOR PHOTODYNAMICTHERAPY .3. CLINICAL-EVALUATION IN THE TREATMENT OF PREMALIGNANT NONMELANOMA SKIN-CANCER

The efficacy of a prototype non-laser light source for photodynamic th erapy was assessed in clinical practice in the treatment of Bowen's di sease and actinic keratoses. The light source, incorporating a 300 W s hort are plasma discharge, was adjusted by appropriate filters to prod uce a bandwidth of 630 +/- 15 nm. Topical 5-aminolaevulinic acid was a pplied 4 h before irradiation to permit production within the lesion o f the active photosensitizer, protoporphyrin IX. Individual lesions re ceived 94-156 J cm(-2). Twenty lesions of Bowen's disease and four act inic keratoses were treated in 12 patients. Patients were reviewed at monthly intervals and treatment repeated if residual disease was prese nt. Clearance was achieved with a single treatment in 15 lesions and i n all of the remaining nine lesions after a second treatment. The trea tment was well tolerated, with pain absent or mild during treatment in 22 lesions, with only one lesion requiring local. anaesthesia. Over t he 10 days following treatment, no pain was associated with 21 treated lesions. During a 12 month follow-up period, two Bowen's disease lesi ons recurred. The overall complete response rate was 92%. Scarring was evident following PDT in only three lesions. Photodynamic therapy usi ng this portable non-laser light source appears to be an effective and well-tolerated treatment for Bowen's disease and actinic keratoses.