Abstract
Cancer is relatively common in birds, and ofthe 27 orders of the Aves class, psittaciformbirds have the highest reported incidence of neoplasia. In fact, neoplasms are more commonly reported in the budgerigar than in any other vertebrate animal. Despite the fact that cancer is a common problem in companion birds, treatment for avian patients with neoplasms has lagged far behind the technology available for other companion animals. This paper will focus on a few of the most common types of cancer that affect companion parrots, diagnosis, and the medical and surgical treatment options available.
Neoplasms of the integumentary system are common in psittacine birds and reportedly account for anywhere from 12 to 70% of all avian neoplasms. Lipomas and fi brosarcomas are the most frequently observed.
Lipomas (benign fatty tumors) are the most common neoplasm of companion birds, with a reported incidence of 10% to 40% in budgerigars. Diagnosis is usually easily made from aspiration of the mass. Lipomas can be large and may interfere with normal locomotion and breeding. Surgical excision is often necessary if the tumor is causing clinical problems. Lipomas can be highly vascular in birds and hemostasis is of the utmost importance. The Cavitron Ultrasonic Surgical Aspirator (CUSA System 200, Valleylab, Boulder, CO, USA) has been shown to have a wide variety of surgical applications in humans, dogs and other mammals. The CUSA is an ultrasonically powered aspirator that selectively fragments and aspirates parenchymal tissue while sparing vascular or ductal structures. The CUSA’s potential applications in avian species is just beginning to be explored at UGA. Preliminary evaluation suggests that when used to resect lipomas in avian patients, the CUSA may provide decreased tissue necrosis and hemorrhage, increased visibility, and shortened operating and recovery times in comparison to more conventional surgical methods such as cold knife, bipolar cautery and CO2 laser. Other integumentary neoplasms seen in birds include lymphosarcoma, fi brosarcoma, and squamous cell carcinoma, to name some of the most common. Diagnosis is usually via surgical biopsy. Treatment may involve radiation therapy, chemotherapy, surgical removal, or other modalities.
For most humans and mammalian companion animals, radiation therapy is an important part of treatment for many of these neoplasms. An understanding of the tolerance of normal tissues included in the treatment field is essential in radiation treatment planning for any animal. Dose response and normal tissue injury have been evaluated extensively in many companion animals. However, there have been no controlled studies of external beam radiation therapy in any avian species. Currently used dosages for external beam megavoltage radiation therapy in birds have been extrapolated from mammalian patients and often appear to provide...