Page 1331 - Clinical Small Animal Internal Medicine

138 Tumors of the Eye and Ocular Adnexa 1269

The value of chemotherapy and radiation therapy Prognosis
VetBooks.ir (RT), either alone or as an adjunct to surgery, is unclear, The prognosis for most tumors involving the orbit and
although chemotherapy for orbital lymphoma may be
optic nerve is poor with conservative treatment, especially
effective. Systemic corticosteroids may reduce perineu-
ronal swelling and permit some patients with optic nerve if there is bony involvement. Recurrence at the original site
and involvement of adjacent or distant sites are common,
meningioma to maintain vision for several weeks to often occurring within weeks to a few months. Even
months. RT may be helpful in the case of nasal tumors benign‐appearing tumors such as lobular orbital adeno-
with orbital extension, in subtotally excised or recurrent mas and orbital meningiomas may be locally invasive and
tumors, and in other select cases. tend to recur following wide excision.
The ocular side‐effects of conventional external beam
RT for nasal and periocular tumors can have a substantial
impact on an animal’s quality of life. Common compli- Secondary Orbital Tumors
cations include keratoconjunctivitis sicca, corneal
ulceration, enophthalmia, entropion, cataracts, retinal Most feline orbital tumors are epithelial in origin, with inva-
hemorrhages, retinal detachments, and blindness. sive SCC being the most common. Lymphoma is another
Intensity‐modulated RT (IMRT), which uses conformal common secondary orbital tumor affecting both cats and
avoidance, significantly decreases the ocular toxicity seen dogs. Orbital lymphoma should be considered part of a
in dogs treated by RT for sinonasal and orbital tumors. systemic process, and further diagnostics are warranted.

Further Reading

Dubielzig RR, Ketring KL, McLellan GJ, Albert DM. tumors treated with intensity‐modulated radiation
Veterinary Ocular Pathology: A Comparative Review. therapy. Vet Radiol Ultrasound 2010; 51(5): 561–70.
New York: Elsevier, 2010. Maggs DJ. Eyelids. In: Maggs D, Miller P, Ofri R, eds.
Featherstone HJ, Renwick P, Heinrich CL, Manning S. Slatter’s Fundamentals of Veterinary Ophthalmology, 5th
Efficacy of lamellar resection, cryotherapy, and edn. St Louis, MO: Elsevier, 2013, pp. 110–39.
adjunctive grafting for the treatment of canine limbal Miller PE, Dubielzig RR. Ocular tumors. In: Withrow S,
melanoma. Vet Ophthalmol 2009; 12(1): 65–72. Vail D, Page R, eds. Withrow and MacEwen’s Small
Lawrence JA, Forrest LJ, Turek MM, et al. Proof of Animal Clinical Oncology, 5th edn. St Louis, MO:
principle of ocular sparing in dogs with sinonasal Elsevier, 2013, pp. 597–607.