Leukemia (Chronic) in Dogs

PetMD Editorial
By PetMD Editorial on Feb. 22, 2010
Leukemia (Chronic) in Dogs

Chronic Lymphocytic Cancer in Dogs

Chronic lymphocytic leukemia is a rare form of cancer which involves abnormal and malignant lymphocytes in the blood. An integral component to the immune system, lymphocytes can affect many body systems when damaged.

This form of leukemia is rare, but more commonly affects male dogs when compared to females.


The symptoms for chronic lymphocytic leukemia are usually non-specific and may include:

  • Increased thirst (polydipsia) and consumption of water
  • Increased urination (polyuria)
  • Enlargement of lymph nodes
  • Fever
  • Lameness
  • Bruises


The following are suspected but unproven risk factors for chronic lymphocytic leukemia:

  • Exposure to ionizing radiation
  • Cancer-causing viruses
  • Chemical agents


You will need to give a thorough history of your dog’s health, including the onset and nature of the symptoms, to your veterinarian. He or she will then perform a complete physical examination, as well as a biochemistry profile, urinalysis, and complete blood count (CBC). Blood testing may reveal anemia, abnormally low number of platelets (cells involved in blood clotting), and abnormal increase in number of lymphocytes in blood film observed under microscope. Your pet’s veterinarian will also conduct a bone marrow biopsy, which will provide a more detailed picture into the abnormalities in lymphocyte production.


If the dog is displaying no symptoms, your veterinarian may recommend against treatment. Otherwise, chemotherapy remains the most popular form of treatment. A veterinary oncologist will be able to devise a treatment plan based on the dog and stage of the disease. In some patients, the spleen may need to be removed to avoid complications.

Living and Management

Regular monitoring and checkups are necessary to evaluate the dog's response to treatment and the progression of the disease. Moreover, regular blood, cardiac, and body system testing will be required if the dog is undergoing chemotherapy. This is because dogs are more prone to infection when taking chemotherapeutic drugs. In case of serious complications, your veterinarian may reduce dosages or stop the treatment altogether.

Should you be required to administer the drugs, your veterinarian will instruct you as to the dosage and frequency. Do not ever increase or reduce the dosage of drugs without prior consulting with your veterinarian. These chemotherapeutic agents are just as toxic to humans, and should only be administered under strict guidelines.

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