title: Retrospective study and review of ocular radiation side effects following external-beam Cobalt-60 radiation therapy in 37 dogs and 12 cats.
abstract: This retrospective study evaluated the ocular side effects of cancer-bearing dogs and cats treated with external-beam Cobalt-60 (Co-60) radiation in which one or both orbit(s) were included in the radiation field. A total of 37 dogs and 12 cats presented to the Ontario Veterinary College during the 10-year study period (1999-2009) were evaluated. The radiation protocols ranged from a maximum of 60 Gray (Gy) in 24 fractions for curative intent to a minimum of 8 Gy in 1 fraction for palliative treatment. The main ocular side effect reported in both dogs and cats was conjunctivitis (79% and 55%, respectively). Other common ocular side effects included eyelid lesions in dogs (44%), ulcerative keratitis in cats (36%), and keratoconjunctivitis sicca in both dogs and cats (44% and 27%, respectively). The high incidence of ocular side effects in both patient populations indicates a need for regular ophthalmic examinations as a component of routine follow-up for radiation therapy involving the orbit. Radiation damage to ocular tissues is also reviewed.
authors.affiliation: Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Guelph, Ontario. cpinard@uoguelph.ca
authors.forename: Chantale L
authors.initials: CL
authors.lastname: Pinard
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Mutsaers
authors.forename: Monique N
authors.initials: MN
authors.lastname: Mayer
authors.forename: J Paul
authors.initials: JP
authors.lastname: Woods
mesh_terms: D000818:Animals; D002371:Cat Diseases / Q000453:epidemiology / Q000209:etiology*; D002415:Cats; D003037:Cobalt Radioisotopes; D003231:Conjunctivitis / Q000453:epidemiology / Q000209:etiology / Q000662:veterinary*; D004283:Dog Diseases / Q000453:epidemiology / Q000209:etiology*; D004285:Dogs; D005128:Eye Diseases / Q000453:epidemiology / Q000209:etiology / Q000662:veterinary*; D005260:Female; D008297:Male; D009369:Neoplasms / Q000532:radiotherapy / Q000662:veterinary; D015995:Prevalence; D011878:Radiotherapy / Q000009:adverse effects / Q000662:veterinary*; D011879:Radiotherapy Dosage; D012189:Retrospective Studies
chemical_list: D003037:Cobalt Radioisotopes