Veterinary photodynamic therapy: a review.

Whereas in human medicine photodynamic therapy represents a well-known and recognized treatment option for diverse indications, it is still little known and unfortunately not yet established treatment option for pets. Various photosensitizers and light sources have been used and clinical results have been published. The main indication is a frequently occurring skin tumor in cats: in situ carcinoma/squamous cell carcinoma, mainly found in not or only slightly pigmented areas of the head. For early stages of this tumor, promising results have been published, partly using new, selective drugs to decrease light sensitivity after systemic administration and to increase response rates. Other possible indications are urinary tract neoplasia of dogs and equine sarcoids, the latter representing very common tumors in horses where no effective treatment is known so far. This review article summarizes the role of photodynamic therapy in veterinary medicine.