A Review of Current Treatment Options in the Treatment of Ocular and/or Periocular Squamous Cell Carcinoma in Horses: Is There a Definitive “Best” Practice?

Electrochemotherapy with bleomycin for bilateral ocular squamous cell carcinoma in a horse

OBJECTIVE

To describe the procedure and outcome of electrochemotherapy (ECT) with bleomycin as a first-line treatment for bilateral ocular surface squamous neoplasia (OSSN) in the eye of a horse.

ANIMAL STUDIED

A client-owned 5-year-old Haflinger gelding with limbal-conjunctival squamous cell carcinoma.

PROCEDURES

During general and local anesthesia, injection of bleomycin in the ocular tumor was followed by electroporation, applied with a 15 mm needle electrode, needles held parallel to the ocular surface.

RESULTS

Treatment with ECT resulted in therapeutic electric pulses and complete tumor response with no recurrence during follow-up. Tumor toxicity as a result of treatment was mild, with no adverse effect to normal tissue.

CONCLUSIONS

In this case of bilateral ocular tumors, staged ECT with bleomycin was shown to be a safe and effective treatment with complete tumor remission and no recurrence during the observation period. The result suggests ECT as a possible treatment in ocular tumors, with further research recommended.

Rhomboid blepharoplasty and cryotherapy for the treatment of a squamous cell carcinoma on the lower eyelid in a horse

A rhomboid blepharoplasty can be used to achieve functional and cosmetic eyelid reconstruction at the medial canthus in the horse. Combination of a rhomboid blepharoplasty with cryotherapy is a treatment option for eyelid ocular squamous cell carcinomas.

Ophthalmologic Disorders in Aged Horses

Ocular abnormalities are a common finding in aged horses. Although these seldom cause overt visual deficits detected by their owners, they can be a source of chronic or acute discomfort so early detection, and treatment when available, is essential. Some of these abnormalities are specific to old horses, whereas others are a result of ongoing disease or inflammation that started earlier in life but that becomes more evident when the damage sustained to the eye is advanced. If vision is significantly affected, consideration of human safety and animal welfare is paramount.