Bexfield, N. H., A. J. Stell, et al. (2008). “Photodynamic Therapy of Superficial Nasal Planum Squamous Cell Carcinomas in Cats: 55 Cases.” Journal of Veterinary Internal Medicine 22(6): 1385-1389.
Squamous cell carcinoma (SCC) is a common skin tumour found in cats. It often affects areas that are non-pigmented and with little hair, such as the nose, eyelids, and ears. Conventional therapies for SCC include surgery and radiation. Photodynamic therapy (PDT) is a cancer therapy that uses visible light to activate photosensitizer agents that localize in the target tissue. The photosensitizing agent 5-ALA can be administered topically, and has previously been evaluated for feline cancer therapy in a small study. Fifty-five cats with SCC of the nose referred to the Queen’s Veterinary School Hospital (University of Cambridge, UK) were enrolled in the prospective study. The 5-ALA cream was applied topically every 30 minutes for a period of 6-8 hours. The cats were lightly sedated and medicated for pain, and all wore an Elizabethan collar. Illumination of the lesions was performed with light emitting diodes while the patients were under general anesthesia. Cats were reassessed one month after PDT. Outcomes were defined as complete response, partial response, or no response. Ninety-six percent of the cats responded to therapy, with 85% having a complete response. However, there was a recurrence rate of 51% at a median interval of 157 days. Although PDT does not lead to a complete remission in all SCC cases, it has the benefit of being safe, well tolerated, and cosmetically acceptable.
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Hammond, G. M., I. K. Gordon, et al. (2007). “Evaluation of strontium Sr 90 for the treatment of superficial squamous cell carcinoma of the nasal planum in cats: 49 cases (1990-2006).” J Am Vet Med Assoc 231(5): 736-41.
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