Treatment of Exuberant Granulation Tissue in an Umbrella Cockatoo (Cacatua alba) with Strontium Radiation.

A 26-year-old female umbrella cockatoo (Cacatua alba) was presented for reoccurrence of a soft tissue mass extending from a fractured area of the rhinotheca. The mass was originally observed 12 years before, after unknown trauma. Histopathology after initial removal was consistent with inflammatory granulation tissue. The mass reoccurred 3 additional times in the same location despite surgical removal and cryogenic therapy. On the fourth surgical resection, strontium-90 radiotherapy was applied to the site immediately after the surgical procedure. No recurrence of the tissue mass from this location has been observed for almost 2 years. This case demonstrates the novel use of strontium radiotherapy to treat exuberant granulation tissue in a bird.

Radiation Therapy of Periorbital Lymphoma in a Blue-and-Gold Macaw (Ara ararauna).

An adult male blue and gold macaw (Ara ararauna) was presented for evaluation of a right periorbital mass. Results of diagnostic tests, including periorbital ultrasound, fine-needle aspirate, and cytologic examination, confirmed a diagnosis of periocular lymphoma. Radiographs were suggestive of disseminated disease but because of concerns about the patient's quality of life, localized radiation therapy to address the periorbital disease was pursued. Coarse-fractionated radiation therapy was initiated, and the mass regressed rapidly during the 3-week course of treatment. The macaw tolerated the treatments well, maintained vision in the affected eye, and activity level and appetite improved. Three months after treatment was completed, the bird died. Necropsy revealed T-cell-rich B-cell-infiltrative lymphoma of the spleen, liver, and kidneys, with some residual neoplastic cells found in the right periorbital region. This case demonstrates a radiation therapy protocol that reduced a tumor mass in a localized treatment of periorbital lymphoma in a macaw.

External Beam Radiation Therapy of Squamous Cell Carcinoma in the Beak of an African Grey Parrot (Psittacus timneh).

Squamous cell carcinoma has been reported in a variety of bird species, most commonly psittacine and gallinaceous birds. The long-term prognosis in nongallinaceous birds is generally poor if complete surgical excision is not possible. Squamous cell carcinoma of the rhinotheca was diagnosed in a 34-year-old timneh African grey parrot (Psittacus timneh) with a 2-year history of beak abnormalities. No evidence of metastasis or local invasion were found on results of radiographs or computed tomography scan. The bird was treated with surgical debulking and palliative megavoltage radiation therapy. After 4 radiation treatments, the affected tissue was necrotic and was debrided to reveal healthy granulation tissue. The bird died approximately 7 months after diagnosis and 4 months after cessation of radiation treatment. At the time of death, a small scab lesion remained at the left oral commissure, but no visible tumor regrowth was evident. A postmortem examination was not performed, however, and tumor recurrence could not be ruled out in this bird.

A survey of veterinary radiation facilities in 2010.

A survey of veterinary radiation therapy facilities in the United States, Canada, and Europe was done in 2010, using an online survey tool, to determine the type of equipment available, radiation protocols used, caseload, tumor types irradiated, as well as other details of the practice of veterinary radiation oncology. The results of this survey were compared to a similar survey performed in 2001. A total of 76 facilities were identified including 24 (32%) academic institutions and 52 (68%) private practice external beam radiation therapy facilities. The overall response rate was 51% (39/76 responded). Based on this survey, there is substantial variation among facilities in all aspects ranging from equipment and personnel to radiation protocols and caseloads. American College of Veterinary Radiology boarded radiation oncologists direct 90% of the radiation facilities, which was increased slightly compared to 2001. All facilities surveyed in 2010 had a linear accelerator. More facilities reported having electron capability (79%) compared to the 2001 survey. Eight facilities had a radiation oncology resident, and academic facilities were more likely to have residents. Patient caseload information was available from 28 sites (37% of radiation facilities), and based on the responses 1376 dogs and 352 cats were irradiated in 2010. The most frequently irradiated tumors were soft tissue sarcomas in dogs, and oral squamous cell carcinoma in cats.

Intraocular osteosarcoma in an Umbrella Cockatoo (Cacatua alba).

An adult, presumed intact female Umbrella Cockatoo (Cacatua alba), presented with acute hemorrhage from an intraocular mass that perforated through the right cornea. Computed tomography scanning revealed a large soft tissue mass in the right orbit, invading and displacing the globe laterally, and destroying the scleral ossicles. There was no evidence of bony changes of the orbit or extension of the mass into the optic nerve or brain. Exenteration and mass removal were performed, and osteosarcoma was diagnosed via histopathology. Radiotherapy was delivered with an orthovoltage unit to a total dose of 68 Gray delivered in 17 fractions over 6 weeks. The bird recovered well from treatment, but died 2 months after the last radiation session with neurological signs. Necropsy was not performed. To our knowledge, this is the first case of an intraocular osteosarcoma reported in a bird, and the first case of attempted treatment of osteosarcoma in a bird by a combination of surgery and radiation therapy.

Radiation therapy of a malignant melanoma in a thick-billed parrot (Rhynchopsitta pachyrhyncha).

A male thick-billed parrot (Rhynchopsitta pachyrhyncha) was diagnosed with a malignant melanoma of the mandibular beak (gnathotheca). Surgical excision was impossible because of the location of the lesion; a combination of radiation therapy and oral antitumor drugs were used to treat the neoplasm. A whole-body computed tomographic scan showed evidence of metastasis in the lungs; the bird, therefore, was considered to have stage IV disease. Throughout the treatment period, the bird showed no clinical evidence of systemic disease. The bird was given 20 treatments of localized radiation therapy of 2.5 Gray (Gy) for a cumulative dose of 50 Gy. The bird was also treated with piroxicam and cimetidine orally from the time of diagnosis, throughout radiation therapy, and until its death. By the completion of radiation therapy, the initial lesion had decreased considerably in size. The bird survived 2.5 months after radiation therapy was completed but died of complications related to metastatic disease. Necropsy results revealed metastases throughout the body, including lesions in the lungs and liver. To our knowledge, this is the first report of localized radiation therapy and oral antitumor drugs being used to treat malignant melanoma in an avian patient. The radiation therapy did produce tumor response in the form of a reduction in size of the visible tumor.