Bovine cancer eye

Wangaratta Chronicle - North East Regional Extra - - News - with An­drew Col­son. Bvsc (Hons), vet­eri­nar­ian

“CANCER eye” (bovine oc­u­lar squa­mous cell car­ci­noma) is the most com­mon form of cancer in cat­tle.

It is es­sen­tially a skin cancer oc­cur­ring on the eye­lids, third eye­lid and eye­ball and es­ti­mates of its preva­lence vary form 1-20 per cent in some herds.

Over­all, cancer eye rep­re­sents 47 per cent of all can­cers in cat­tle that cause car­cass con­dem­na­tions.

The dis­ease oc­curs al­most ex­clu­sively in cat­tle with ar­eas of un­pig­mented skin around the eyes, with breeds in­clud­ing Here­fords, Poll Here­fords and Friesians be­ing the most sus­cep­ti­ble.

Cancer eye has been shown to be mod­er­ately her­i­ta­ble in that skin pigmentation and fa­cial con­for­ma­tion is her­i­ta­ble.

Other rec­og­nized risk fac­tors in­clude pro­trud­ing eye­balls be­ing more sus­cep­ti­ble than the “hooded” breeds and pro­longed ex­po­sure to ul­travi­o­let ra­di­a­tion. Cancer eye in Here­fords is al­most un­heard of in the UK where the breed orig­i­nates.

Cancer eye be­gins as a small, pink, pro­lif­er­a­tive growth al­though there may be some crusty, scabby pre­cur­sors if it is on one of the eye­lids (usu­ally the lower one).

Specif­i­cally eye can­cers oc­cur in three sites: the eye­lids proper (up­per and lower), the third eye­lid (a small flap lym­phatic tis­sue in the me­dial cor­ner of the eye), and on the eye­ball it­self. Oc­u­lar can­cers may re­main the same size for many months but then be­gin to grow rapidly in all direc­tions form­ing grotesque, putrid masses that can be­come in­fected and fly struck.

The can­cers can also grow in­ward and al­though cancer eyes do not metas­ta­size (spread in the blood) quickly, they do tend to be lo­cally in­va­sive spread­ing into the sur­round­ing tis­sue and lym­phatic ves­sels.

It is re­garded as an of­fence un­der the Preven­tion of Cru­elty to An­i­mals Act to al­low a cancer eye to de­velop to the ad­vanced stages and own­ers fail­ing to cull or treat such an­i­mals may face pros­e­cu­tion if the an­i­mal is not im­me­di­ately treated or de­stroyed.

Many cases of bovine cancer eye can be treated quite suc­cess­fully by a vet­eri­nar­ian es­pe­cially if treated early us­ing ei­ther sur­gi­cal or cryosur­gi­cal (liq­uid ni­tro­gen sprays) meth­ods.

More ad­vanced cases may be treat­able where the eye and the sur­round­ing soft tis­sue is re­moved and this will avoid the ne­ces­sity of culling and may com­pletely re­solve the cancer al­to­gether pro­vid­ing it has not in­fil­trated be­yond the sur­gi­cal field.

If you have any ques­tions about cancer eye in cat­tle please con­tact your vet­eri­nar­ian.

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