By: Dr. Jessica L. Grove
Lymphoma is a malignant form of cancer that can affect both cats and dogs, and originates from solid organs and/or tissues such as lymph nodes, skin, liver, and spleen. In canines, this type of cancer’s etiology is multifactorial, meaning no single cause has been identified. However, there is a known genetic component which makes this neoplasia more common in particular breeds such as Boxers, Rottweilers, Golden Retrievers, and Cocker Spaniels. Most dogs diagnosed with lymphoma are middle age or older (6-12 years old), but it can occur in dogs of any age, even in puppies.
There are 4 anatomic classifications for lymphoma:
- 1) Multicentric – generalized enlarged lymph nodes +/- liver, spleen or bone marrow involvement
- 2) Mediastinal
- 3) Alimentary – GI tract +/- intraabdominal lymph node involvement
- 4) Extranodal – affects any organ or tissue like the skin, eyes, kidneys, lungs, or CNS
The most common form in dogs in multicentric. On physical exam, a veterinarian will typically find significantly enlarged lymph nodes (5-15 times normal size) that are painless and freely movable.
The diagnosis of lymphoma is confirmed via cytologic evaluation of a FNA (fine needle aspirate) and/or using histopathology. Owners who contemplate therapy should have bloodwork (CBC/Chem), a urinalysis, and imaging (radiographs and ultrasonography) performed, which provides a wealth of information to both the owner and clinician in terms of deciding whether to treat the patient. Treatment is chemotherapy and there are numerous protocols available. A cat or dog’s overall prognosis is poor in terms of long-term survival. Remission rates in those treated with various chemotherapy protocols are between 65-75% and 80-90%. Depending on the type of lymphoma present, a treated cat or dog may have a life expectancy of 6-9 months or possibly 1 or 2 years.
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