5.08] Fluorescence diagnosis and photodynamic therapy of superficial squamous cell carcinomas in cats using topical 5-aminolevulinic acid and incoherent light sources

Abstract

Objective In human medicine photodynamic therapy (PDT), utilizing the topical administration of 5-aminolevulinic acid (5-ALA) has generated widespread interest in the past several years and is rapidly becoming the standard treatment for multiple actinic keratosis in several countries. In cats, UV-induced superficial squamous cell carcinomas have been treated with PDT using systemic sensitizers and diode lasers. The effect of topical 5-ALA as a 20%-creamor as 10%-gelin squamous cell carcinomas in cats is demonstrated. Material and methods In total 15 cats with squamous cell carcinomas on the pinna or the nose have been treated with PDT. 5-ALA was applied topically for 4–6 h under occlusion while the animals were sedated. Before radiation with an incoherent light source and a fluence of 180 J/cm 2 was applied, photographs of the fluorescence were taken using a digital camera with a mounted long pass filter. Results In more than 80% of the cases, one single treatment was curative. Conclusion Superficial squamous cell carcinomas in cats can be effectively treated with topical 20%-ALAcream or 10%-ALAgel and using incoherent light sources.