Modified topical photodynamic therapy of superficial skin tumors, utilizing aminolevulinic acid, penetration enhancers, red light, and hyperthermia.

Abstract

Photodynamic therapy (PDT) is a noninvasive selective therapy for a specific group of skin tumors. In this study we used a modified topical medication in which ethyleneamine tetra acetic acid (EDTA) and dimethylsulphoxid (DMSO) were added to 5-aminolevulinic acid 20% (ALA) followed by exposure to a novel high output light source emitting red and infrared irradiation. ALA 20%-EDTA 2%-DMSO 2% in a water in oil cream base was applied to the tumors. After 12 hours the tumor was exposed to red (585-720 nm; 150 mW/cm2) and near infrared irradiation (1.25-1.6 mm; 50 mW/cm2) for 10-15 minutes by the VersaLight incoherent filtered light source. Complete responses were achieved after one to three ALA-PDT treatments in 26/31 lesions of superficial or small nodular basal cell carcinoma (BCC) (84%), and in four of five in superficial squamous cell carcinoma (SCC) (80%). Complete clearance was achieved in one patient with Bowen's disease of the penis. Topical PDT utilizing ALA 20%-EDTA 2%-DMSO 2% as the photosensitizer and VersaLight as the light source is a noninvasive, nearly painless treatment with excellent therapeutic and cosmetic results. Our data show the efficiency of this therapy for patients with certain subtypes of BCC, SCC, and Bowen's disease.