Oncological Applications of Photodynamic Therapy in Dogs and Cats

Abstract

Photodynamic therapy (PDT) in small animals’ oncology has been under research focus, pointing to new treatment possibilities. Moreover, several animal studies constitute experimental human disease models due to the similarity of tumor biology between animals and man. PDT uses photosensitizing compounds without toxicity per se. When subjected to a specific wavelength, the photosensitizers are activated, triggering the production of reactive oxygen species (ROS) that lead to cell death. Additionally, antiangiogenic effects and immune stimulation may also be elicited. PDT is minimally invasive, non-toxic, and does not induce carcinogenic or mutagenic side effects. Thus, it is safe for non-neoplastic tissues compared with other neoplasms treatment modalities. This review describes the applications of PDT in the cancer treatment of small animals, particularly dogs and cats, focusing on the respective photosensitizers and treatment protocols used in trials in this therapeutic modality.

Vascular‐targeted photodynamic therapy with glucose‐conjugated chlorin e6 for dogs with spontaneously occurring tumours

“…The interaction between light and the administered photosensitiser induces a photochemical reaction that generates highly reactive species, termed singlet oxygen ( 1 O 2 ) or radicals (van Straten et al., 2017; Gunaydin et al., 2021). In veterinary medicine, there have been several reports on the use of PDT (Dobson et al., 2018; Guimarães et al., 2022). Although PDT is safe and effective for a variety of tumours in dogs and cats, it does not always ensure an effective therapeutic outcome.…”

Influence of age and breed of dogs on tumour development

“…Considering the similarities between cancers in dogs and humans, makes these pets, according to T.G. Guimarães et al (2022), the best biological subjects to study the therapeutic effects of different treatments on the body for their subsequent application in human therapy.…”