Bone marrow transplantation for dogs with lymphoma

Bone Marrow Transplant for Dogs with Lymphoma
(By VCA West Los Angeles Animal Hospital)

Bone Marrow Transplantation
Canine bone marrow transplantation for lymphoma is the replacement of irradiated bone marrow with normal stem cells
after chemotherapy is concluded. It allows veterinary oncologists to treat lymphoma with the most aggressive
chemotherapy possible. They can administer a dose of total body irradiation high enough to kill lymphoma cells that may
be resistant to chemotherapy or residing in locations in the body where chemotherapy cannot reach.

There are two main types of transplantation. Allogenic transplantation takes compatible stem cells from one patient and
gives them to another. Autologous transplantation removes the dog’s own stem cells, which are then put back into the dog.
These stem cells used to be taken from the bone marrow, requiring a painful and invasive procedure. Today, they are
obtained directly from the blood. This procedure is more accurately called Hematopoietic Stem Cell Transplantation (HCT).
Allogenic transplantation is possible, but due to a lack of a national animal registry for stem cell donors, most
transplantations in dogs are autologous.

How is Transplantation Performed?
The patient will first undergo a battery of tests to determine physical capability for undergoing the transplant procedure.
This testing will also provide the veterinary oncologist with information that will help tell when the patient is in complete
remission from the disease and able to undergo the transplantation process, which is outlined below:

Consolidation Chemotherapy: Once in remission, your pet will receive a single high dose of a chemotherapeutic agent.
This treatment, termed consolidation, clears any remaining cancerous cells from the blood stream, where the stem cells will
be collected.

Stem Cell Mobilization: After your pet’s white blood cells and platelets have recovered, additional testing will ensure that
no other diseases or signs of cancer are present. Your pet will then receive twice daily injections at home of a medication
that promotes white blood cell proliferation, as well as oral antibiotics to help remove bacteria from the intestinal tract. In six
days, your pet will be ready to undergo stem cell collection, called apheresis.

Apheresis: Your pet will be sedated or anesthetized in order to remain completely still during the collection procedure,
which can take four to six hours. Intravenous catheters are placed and stem cells for transplantation are filtered out of your
pet’s blood. The rest of your dog’s blood is returned.

Transplantation: Patients undergo total body irradiation (TBI) 24 hours after apheresis in order to eradicate any
remaining lymphoma cells. However, this destroys all normal white blood cells, as well. Therefore, immediately after
radiation, the healthy stem cells collected from your pet the previous day are re-infused (transplanted) back into your pet
intravenously.

Recovery: During the next 10 to 14 days following transplantation, dogs will be hospitalized in a dedicated clean
environment where they can be protected from harmful bacteria and viruses. During this time their irradiated white cells
and platelets will die and eventually be replaced by the transplanted stem cells. Patients receive 24-hour care and
observation during their stay. This is the most critical aspect of transplantation because certain complications—
hemorrhage, infection, or complications due to radiation—although rare, may occur.

Follow-up: If successful, further chemotherapy for lymphoma will not be required. However, to make certain a cure has
occurred, your veterinarian will schedule regular follow-up appointments for physical examination and testing.

Who is a Candidate for Bone Marrow Transplantation?
Any dog with lymphoma is a potential candidate for transplantation. However, depending on the specific type of lymphoma,
ability to obtain a remission, age, weight, and the presence of other concurrent diseases, some patients will be better
candidates than others. Whether or not your pet is a candidate for transplantation should be carefully discussed with your
veterinarian early in the course of therapy.