An 8-year-old female spayed DSH referred for radiation therapy of multiple progressive Bowenoid carcinoma and Squamous cell carcinoma lesions on the head / face.
Owner noted lesions over the right and left periauricular and left lateral muzzle in August 2018. These lesions were scabbing and crusting and progressed to be more numerous and covering a larger area of dermis resulting in irritation to the patient. Biopsies were done at rDVM on 27/9/2018 and were consistent with Bowenoid carcinoma in situ on the right pinna and left nasal plane as well as early SCC over the right preauricular region. Patient was started on topical imiquimod cream but the legions progressed and application was associated with notable skin inflammatory reaction. Patient has a history of “cat flu” and viral stomatitis being managed with famciclovir and doxycycline but is otherwise well. Patient was referred to the oncology service for evaluation and treatment options on 27/2/2019.
Blood work done on 27/9/2019 was all within normal limits. Previous thoracic radiographs from RDVM were unremarkable.
Given the extent of the lesions and superficial involvement of the dermis, patient was considered a reasonable candidate for Strontium 90 radiation therapy to manage the most refractory lesions. The intent was to evaluate response of treated sites as an internal control with additional future treatments to be done as needed if successful. Treatment of 3 zones of affected dermis including right periauricular tissue, left nasal plane and left ventral eyelid region was done. All sites were treated with a single dose of 90Gy delivered in multiple overlapping fields. A short 5-day course of meloxicam was administered post treatment.
The treatment lesions responded very favourably with significant improvement in crusting and scabbing lesions at the 6-week post radiation recheck on 8/4/2019. No significant adverse effects were reported by the owner. At 28 months post treatment the patient was doing very well with no relapse in treated areas