Photodynamic therapy and diagnosis: Principles and comparative aspects.
Authors: Dobson Jane, de Queiroz Genilson Fernandes, Golding Jon P
Journal: Veterinary journal (London, England : 1997)
Summary
# Editorial Summary: Photodynamic Therapy in Veterinary Medicine Photodynamic therapy (PDT) represents a non-invasive approach to treating superficial tumours by combining tumour-selective photosensitiser dyes, tissue oxygen and targeted light delivery to generate cytotoxic reactive oxygen species directly within malignant tissue. Beyond direct tumour cell destruction, PDT damages the tumour's microvasculature and triggers local inflammatory and systemic immune responses, whilst leaving surrounding extracellular matrix largely intact—resulting in superior tissue healing and minimal scarring compared with surgery or radiotherapy. The fluorescent properties of photosensitiser dyes enable dual functionality: tumour visualisation during treatment planning and intraoperative guidance, which can substantially improve surgical accuracy and margins. Equine practitioners have successfully applied PDT for treating sarcoids, whilst veterinary colleagues have documented efficacy in feline nasal planum squamous cell carcinomas and canine urinary tract, bladder and prostate neoplasia. This comparative literature review across human and veterinary medicine establishes PDT's potential as a valuable addition to the therapeutic toolkit for superficial neoplasia, though further development and standardisation of protocols within equine practice remain necessary to optimise outcomes and define its precise role alongside conventional treatment modalities.
Read the full abstract on PubMed
Practical Takeaways
- •PDT represents a non-invasive alternative for managing equine sarcoids and other superficial neoplasias with minimal scarring and rapid tissue healing
- •The dual diagnostic and therapeutic capability of photosensitiser dyes could improve surgical planning by allowing better tumor visualization before treatment
- •PDT's mechanism of action through immune stimulation and vascular disruption offers advantages over traditional therapies, though further veterinary research is needed to establish optimal protocols
Key Findings
- •PDT is a non-invasive tumour treatment that generates cytotoxic reactive oxygen species and damages tumour microvasculature while preserving surrounding extracellular matrix
- •Photosensitiser dyes used in PDT are fluorescent and selectively accumulate in tumour tissues, enabling both treatment and visualization for improved surgical accuracy
- •PDT has been successfully applied in veterinary medicine for superficial squamous cell carcinomas in cats, urinary and prostate neoplasia in dogs, and equine sarcoids
- •PDT causes minimal tissue scarring and excellent healing compared to surgery or radiotherapy, with local inflammatory response stimulating immune response against tumours