Canine Lymphoma
Lymphoma (lymphosarcoma, LSA) is a cancer of the lymphocytes (white blood cells) most commonly originating in the lymph nodes (lymph glands), although it may affect any organ, including spleen, liver, intestines, and skin. Fortunately, most (~90%) patients treated with combination chemotherapy undergo clinical remission (no visible evidence of cancer) for extended periods of time.
During your appointment with The Ohio State University Veterinary Teaching Hospital Oncology/ Hematology Service, your dog's previous history and diagnostic findings will be reviewed. In most cases, fine-needle aspiration cytology will be done to assist in confirming the diagnosis, particularly if a previous biopsy is not available. A tissue biopsy (usually done under sedation with a slightly larger needle) often also is obtained to confirm the cytologic diagnosis and to provide additional information. Additional diagnostic procedures may be required, including abdominal ultrasound, thoracic radiographs, bone marrow aspirate, urinalysis, and blood samples for a complete blood count (CBC) and serum chemistry profile. All of this information assists in making a diagnosis of lymphoma, and assessing the extent of disease and suitability for treatment.
Lymphoma in most instances is a very chemotherapy responsive disease. For most patients, chemotherapy using a combination of drugs is recommended. During the "induction phase" of chemotherapy, patients receive intravenous injections of drugs on a weekly basis as well as some oral drugs at home. After completion of induction therapy, some patients will continue to receive maintenance therapy consisting of oral drugs alone, or in combination with intravenous drugs. On average, about half of treated patients live over one year beyond the initiation of chemotherapy and 20% for longer than 2 years. Some treatments (ie. UW-19 protocol) uses chemotherapy for only a limited period of time (ie. 19 weeks).
Chemotherapy is well-tolerated by most dogs. Possible side-effects include nausea, vomiting, diarrhea, inappetence, and myelosuppression (low blood cell counts), but is self-limiting in most instances. Hospitalization due to chemotherapy-related complications is rare (~5-7%). Quality of life for dogs with lymphoma on chemotherapy, as judged by the owners, usually is excellent.
