Abstract:
Photosan, a mixture of porphyrin oligomers as sensitizer for photodynamic therapy (PDT), carry the risk of prolonged photosensitivity of the skin. New sensitizer such as 5-aminolaevulinic acid (ALA) with low rates of skin phototoxicity appear to be promising alternatives. The aim of this study was to evaluate the efficacy of ALA compared to Photosan for PDT in malignant tracheo-bronchial stenosis. Reduction of tumor stenosis, increase in quality of life, and phototoxicity were considered as primary objectives. Improvement in clinical symptoms due to reduction of tumor stenosis, for example hemotysis, dyspnea, and poststenotic pneumonia were considered as secondary objectives. After diagnostic work-up, photosensitization was done in 16 patients with ALA (60 mg/kg BW, oral, 6-8 hours prior to PDT) and in 24 patients with Photosan (2 mg/kg BW, i.v., 48 hours before PDT). The light dose was calculated as 100 J/cm(2) tumor length. Light at 630 nm was applied using a pumped dye laser. In both groups, additional hyperbaric oxygenation was applied at a level of 2 absolute atmospheric pressure. Stenosis diameter and Karnofsky performance status showed a significant improvement in favor of the Photosan-group, P = 0.00073 and 0.00015, respectively. In both groups no sunburn occurred due to phototoxicity of the sensitizer. Despite the limitations of a non-randomized study, photosensitization with Photosan seems to be more effective in PDT of malignant tracheo-bronchial stenosis compared to ALA.
Maier, Tomaselli, Matzi, Woltsche, Anegg, Fell, Rehak, Pinter, (2002). Comparison of 5-aminolaevulinic acid and porphyrin photosensitization for photodynamic therapy of malignant bronchial stenosis: a clinical pilot study. Lasers in surgery and medicine, 2002 ;30(1):12-7. https://www.ncbi.nlm.nih.gov/pubmed/11857598