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Local photodynamic therapy delays recurrence of equine periocular squamous cell carcinoma compared to cryotherapy
Author(s) -
Giuliano Elizabeth A.,
Johnson Philip J.,
Delgado Cherlene,
Pearce Jacqueline W.,
Moore Cecil P.
Publication year - 2014
Publication title -
veterinary ophthalmology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.594
H-Index - 50
eISSN - 1463-5224
pISSN - 1463-5216
DOI - 10.1111/vop.12099
Subject(s) - cryotherapy , medicine , photodynamic therapy , surgery , exact test , log rank test , cyberknife , radiation therapy , survival analysis , radiosurgery , chemistry , organic chemistry
Objective (i) To report the successful treatment of 10 cases of equine periocular squamous cell carcinoma ( PSCC ) with surgical excision and photodynamic therapy ( PDT ) using verteporfin. (ii) To evaluate time to first tumor recurrence between PDT ‐treated horses and horses treated with surgical excision and cryotherapy. Methods A total of 24 equine PSCC cases were included: group 1 ( n = 14) had excision and cryotherapy (1993–2003), group 2 ( n = 10), excision and local PDT (2006–2010). Evaluated data: signalment, treatment method, tumor location, size, and time to first recurrence. Groups were compared via chi‐square test for categorical variables and W ilcoxon rank‐sum test for numeric variables. Time to tumor recurrence was examined using K aplan– M eier product‐limit survival analysis. Results Of 24 cases, nine breeds were affected. Mean age at treatment in years: 14 (range 5–24) in group 1; 11 (range 8–18) in group 2. Median tumor size: 163 mm 2 (range 20–625 mm 2 ) in group 1; 195 mm 2 (range 45–775 mm 2 ) in group 2. Signalment, tumor laterality, and size were not significantly different between groups. Time to recurrence was significantly different between groups (Logrank test, P = 0.0006). In group 1, 11/14 horses had tumor regrowth with median time to recurrence in months: 10 (range 1–44). In group 2 (minimum follow‐up of 25 months; range 25–50), no horse demonstrated tumor recurrence after one treatment with excision and PDT . Conclusions This represents the first report of local PDT using verteporfin for treatment of equine PSCC . Following surgery, the likelihood of tumor recurrence was significantly reduced with local PDT compared with cryotherapy.