Shedding light on photodynamic therapy for basal cell carcinoma

摘要： The recognition of photodynamic therapy (PDT) as an effective treatment of cancers was due, in large part, to the studies of Thomas Dougherty and his colleagues at Roswell Park Cancer Institute in Buffalo, NY, started in the 1970s.1 In those studies, intravenous porphyrin derivatives and visible light were used. Topical PDT treatment, currently widely performed in dermatology, uses topically applied 5-aminolaevulinic acid (ALA) or ALA esters.2,3 ALA is converted to protoporphyrin IX in the epidermis. On exposure of protoporphyrin IX to its absorption spectrum in the visible light range, oxygen-dependent phototoxic reaction occurs resulting in cytotoxicity.