Page 901 - The Veterinary Care of the Horse
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of healthy tissue, is the treatment of choice. Where clear margins cannot be obtained, surgery
may be combined with topical chemotherapy such as 5-fluorouracil ointment or radiotherapy.
VetBooks.ir EYES
Lesions on the third eyelid (Figure 18.44 and see Figure 21.26) and conjunctiva can be
removed surgically and/or be treated by topical chemo-therapy or radiotherapy. Squamous
cell carcinomas of the cornea and sclera (white) of the eye are surgically removed as far as
possible and respond well to radiation therapy. Radiation is delivered by a procedure known
as strontium plesiotherapy, whereby a radioactive source is applied directly to the tumour
surface (Figure 18.45). This only penetrates a short distance and surrounding or deeper
tissues are not damaged. Three sessions of 5–10 minutes are given at 48-hour intervals with
the horse under standing sedation or general anaesthesia. The horse can be handled normally
after the treatment. Radiotherapy is only available at a specialist centre. In the UK it is
available at the Animal Health Trust, Newmarket.
Figure 18.44 Squamous cell carcinoma of the third eyelid (see also Figure 21.26)
