Photosensitizers and light sources for photodynamic therapy of the Bowen’s disease

Bowen’s disease is a neoplastic skin disease, known as squamous cell carcinoma in situ. The treatment options for Bowen’s disease are: cryotherapy, curettage, surgery, topical therapy and radiotherapy. In the past recent years, photodynamic therapy was used as a new treatment method. The purpose of this paper is to summarize the results of clinical and research studies with respect to the photodynamic therapy of Bowen’s disease. A search of three databases was conducted using specific keywords and explicit inclusion and exclusion criteria for the study of photosensitizers, light sources and their efficacy in photodynamic therapy of Bowen’s disease. Two photosensitizers have been used mainly for photodynamic therapy of Bowen’s disease therapy: δ-aminolevulinic acid and methyl aminolevulinate. These photosensitizers have been activated with both coherent (lasers) and non-coherent (lamps and LEDs) light sources. Fluence has been set in a large domain (10–240 J/cm2) and irradiance was 0.23–100 mW/cm2. All these light sources have the same efficacy. The high response rates were obtained using methyl aminolevulinate and light emitting diode as light source. These results have demonstrated that photodynamic therapy using methyl aminolevulinate as photosensitizer could be considered as one of the first therapeutic options for Bowen’ disease.