Squamous Cell Carcinoma
Ocular Squamous Cell Carcinoma (Cancer Eye) is the most common tumour of cattle. It is common in various European breeds in Kenya, especially Friesian/Holsteins, and Ayrshires.
- Zebu cattle are rarely affected.
- When it occurs it results in significant economic loss due to condemnation at slaughter and a shortened productive life.
Several factors play a part in causing Squamous Cell Carcinoma, including exposure to sunlight, eyelid pigmentation, genetic predisposition, nutrition and perhaps viral involvement. Ultraviolet radiation and a high plane of nutrition are important factors as are whether the eyelids are pigmented or not. The latter is highly inheritable.
- The lesionsbegin as non-cancerous, smooth, white growths on the eyeball surfaces. These may progress to a papilloma (a small solid benign tumour with a clear-cut border that projects above the surrounding tissue) and then to the cancerous squamous cell carcinoma. Sometimes it goes directly to the cancer stage.
- The eyelids, eyeball surface (third eyelid) and the point where the cornea meets the 'white' of the eye all may be affected and the lesions may be ulcerative.
- Both eyes may be affected at the same time. At this early stage an unexpected improvement or cure may occur in a large number of animals. But the tumour may progress and become quite large and cauliflower-like.
- There is a discharge from the eye which may trickle down the face. The tumour may be large without invading the globe but later invasion into the globe and orbit and spread to local lymph nodes may occur.
- The whole eye may be destroyed accompanied by massive local swelling. At this stage no treatment is possible.
Treatment and Control
- Early treatment is usually successful, either bythe surgical removal of the tumour itself, or, if this is not possible, by surgical removal of the eye.
- Well equipped veterinarians may have other treatment options such as cryotherapy (a technique that uses an extremely cold liquid or instrument to freeye and destroy abnormal cells), hyperthermia (including extreme body temperature), radiation therapy and immunotherapy.
- But the most important factor in control is early treatment, preceeded by constant, close observation, breeding of animals with pigmented faces is important as animals with non-pigmented skins and non-pigmented eyelids are not suited to African conditions. Avoid them.