Multicentric Lymphoma in Dogs

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Lymphoma is the most common cancer in dogs, and the subtype most dogs present with is the multicentric variety. Whereas some lymphomas will begin in a single lymph node, multicentric lymphoma in dogs will originate in multiple lymph nodes spread throughout the body.

Signs and Symptoms

The classic symptom is painless swelling of two or more lymph nodes. These swollen nodes are not yet tumors, per se, although many pet owners will assume that’s what they are. A vet will be able to determine whether they are tumors or lymph nodes based on their specific location on the dog’s body.

Additional symptoms for multicentric lymphoma in dogs are:

  • Sudden, unexplained weight loss
  • Lack of appetite
  • Vomiting or diarrhea
  • Shortness of breath
  • Fever

Most of these symptoms can be caused by other diseases (that is, they are non-specific), so a vet is needed to make a definitive diagnosis.

Diagnosis

In dogs, the vet will typically begin by palpating or feeling the lymph nodes by hand. If he determines they are abnormally swollen, he may draw a sample of lymph, a fluid used transport white blood cells and other cells of the immune system. This sample can provide cells for analysis. If there are not enough cells present, the vet may need to biopsy the node. Due to their size, dogs usually have the entire node surgically removed for study, a procedure that requires general anesthesia.

Treatment

If it is determined that the dog has multicentric lymphoma, the standard treatment for canine lymphoma is chemotherapy. Dogs generally do not have the same side effects to chemotherapy drugs as humans (like hair/fur loss), although the exact treatment provided will depend on the exact type of lymphoma the dog has.

Another option is half-body radiation therapy. To get all the affected lymph nodes, the upper half of the dogs body is irradiated one day and the dog is brought back several weeks later to irradiate the lower half. The reason the entire dog isn’t treated at once is that that procedure leaves the dog with a severely compromised immune system. Breaking the treatment into two somewhat mitigates that risk.

Prognosis

The life expectancy of a dog with lymphoma who goes without treatment is less than two months. Multicentric lymphoma in dogs is no exception. With chemotherapy, however, dogs may be expected to survive a year or more. Ten percent or fewer dogs see no improvement from chemotherapy, compared with 75 percent who go into remission.

It is important to realize, however, that a true “cure” for multicentric lymphoma in dogs is rare. Eventually, almost all remissions end in relapse, after which chemotherapy is not nearly as effective, and treatment switches to improving the quality of the life the dog has left.

Photo by John Nyboer

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