Peer-reviewed veterinary case report
Radiation dose linked to dry eye in dogs with nasal tumors
By Poirier, Valerie J et al.·Published in Journal of veterinary internal medicine·2020·School of Veterinary Science·View original on PubMed →
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Original publication title: Clinical-dosimetric relationship between lacrimal gland dose and keratoconjunctivitis sicca in dogs with sinonasal tumors treated with radiation therapy.
- Species:
- dog
Plain-English summary
A group of dogs with nasal tumors that received radiation therapy were monitored for eye problems, specifically keratoconjunctivitis sicca (KCS), which causes dry eyes. Out of 25 dogs treated, 5 developed KCS about 111 days after starting treatment. The study found that dogs whose lacrimal glands received more than 20 Gray (Gy) of radiation were much more likely to develop KCS, while those receiving less than 20 Gy did not show any signs of the condition. To help prevent KCS, it's important for veterinarians to carefully plan radiation doses to the lacrimal glands during treatment.
People also search for: dog dry eyes after radiation · keratoconjunctivitis sicca treatment in dogs · sinonasal tumor radiation side effects
Abstract
BACKGROUND: Dogs with sinonasal tumor can develop keratoconjunctivitis sicca (KCS) after radiation therapy (RT). In humans, the incidence of xerophtalmia is associated with the mean radiation dose received by the ipsilateral lacrimal gland (LG). HYPOTHESIS/OBJECTIVES: The eyes receiving a higher mean LG dose are more likely to develop KCS. The aim of the study was to determine a starting threshold dose to use as dose constraint for intensity-modulated radiation therapy (IMRT). ANIMALS: Dogs with nasal tumors treated with RT between August 2013 and December 2016. METHODS: Case control retrospective study of dogs with sinonasal tumor treated with 42 Gray (Gy) in 10 fractions using IMRT. Dogs were included if development of KCS after RT was documented (cases) or adequate follow-up information with Schirmer tear test (STT) result for ≥6 months after RT was available (controls). Lacrimal glands were contoured and dose distribution was calculated using the original treatment plan to determine prescribed doses to LGs. RESULTS: Twenty-five dogs were treated with RT and 5 dogs (20%) developed KCS. Fifteen dogs met the inclusion criteria including 5 unilateral KCS and 10 control dogs, resulting in 5 KCS eyes and 25 control eyes. KCS developed at a median of 111 days (84-122) after 1st RT. The mean LG dose reached using a 4.2 Gy per fraction was 33.08 Gy (range: 23.75-42.33) for KCS eyes and 10.33 Gy (1.8-24.77) for control eyes (P < .001). The minimum LG mean dose for developing KCS was 23.75 Gy. No eyes that received a mean LG dose <20 Gy developed KCS versus 5/7 (71%) developed with >20 Gy. CONCLUSION AND CLINICAL IMPORTANCE: Contouring and applying a dose constraint on LGs should be performed when using IMRT in dogs with sinonasal tumors to reduce the risk of KCS.
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Search related cases →Original publication on PubMed: https://pubmed.ncbi.nlm.nih.gov/32086981/