Fluorescent Light Energy (
FLE
) as an Adjunctive Therapy in Canine Cutaneous Epitheliotropic Lymphoma (
CTCL
)
S. Nowell, O. Fantini, A. Roman, C. Milley, J. Watson, C. Bauer ABSTRACT
Background
Fluorescent light energy (FLE; Phovia, Vetoquinol) is a photobiomodulation therapy that promotes healing and reduces inflammation. Cutaneous epitheliotropic lymphoma (CTCL) is a neoplastic skin disease with limited treatment options. Although FLE is not considered genotoxic, its use in neoplastic conditions is off‐label.
Hypothesis
To assess the safety and clinical effect of FLE as an adjunctive treatment for canine CTCL.
Animals
Eight client‐owned dogs were diagnosed with CTCL via biopsy analysis and immunohistochemical analysis.
Materials and Methods
Each dog had one CTCL lesion treated with FLE with a lesion serving as a vehicle‐control. Treatments were administered weekly for 6 weeks, followed by 3 months follow‐up. Focal nodular lesions were assessed weekly using Response Evaluation Criteria of Solid Tumours (RECIST), while diffuse lesions were evaluated using the Canine Epitheliotropic Lymphoma Extent and Severity Index (CELESI). Owner‐perceived efficacy and quality of life were assessed using the Owner Global Assessment of Treatment Efficacy (OGATE) and a quality‐of‐life (QoL) survey.
Results
No statistically significant differences in estimated marginal means were observed between sites at any time point ( p > 0.05). Within‐subject analyses suggested more favourable lesion progression at FLE‐treated sites, and 75% of RECIST‐evaluated FLE lesions maintained stable disease. Diffuse FLE‐treated lesions demonstrated clinical severity reductions of ≤ 35.3%. Over 66% of owners rated treatment response as ‘fair’ to ‘excellent’ on the OGATE. One dog was withdrawn at Week 3 as a consequence of unrelated worsening.
Conclusions and Clinical Relevance
FLE appears to be a safe adjunctive therapy for canine CTCL, although statistically significant treatment effects were not demonstrated.