An Update on Canine Lymphoma Treatment

Human Drugs Gone to the Dogs

The current state-of-the-art of treatment for many forms of canine lymphoma is a modification of the chemotherapy protocol used to treat humans with the disease. The protocol uses a combination of the same four drugs used in humans, although at dog-appropriate dosages and on a different treatment schedule. This regimen results in the longest median survival time for dogs with lymphoma, with a median survival time of about 12 months from the time of diagnosis. About 20% of dogs will live more than two years. The prescribed treatment course is approximately six months long and includes prednisone and doxorubicin, among other drugs. The four-drug combination may not suit all patient families or budgets and so it is not universally prescribed for all dogs with lymphoma.

In Rare Cases, No Treatment Needed

Most lymphomas need treatment, but in a small number of cases, this may not be true. Veterinary oncologists and pathologists who have studied canine lymphoma have identified forms of the disease with an ‘indolent course.' These forms of lymphoma are slow to progress and do not typically cause clinical signs. However, these forms are uncommon. The trick is for your veterinarian to parse the biopsy report carefully and determine if your dog is one of the rare lucky dogs with one of these rare forms of lymphoma that need close monitoring but no chemotherapy.

No Surgery? No Radiation?

For most types of cancer, surgery is the mainstay of treatment, but lymphoma is different. In many dogs, a lymphoma diagnosis is based on a needle aspirate. In other dogs, surgery might be used to obtain a biopsy, but oncologists infrequently use it as a treatment. Think about it: Surgery can easily remove a solitary lump or bump, but since lymphoma involves the entire immune system, which is dispersed throughout the body, even the best surgeon in the world would not be able to remove every speck of cancer. Similarly, radiation therapy is rarely used in the treatment of canine lymphoma, unless the disease appears to be in just one location. However, if radiation therapy is used, a course of chemotherapy is also typically administered. While dog families might be concerned about chemotherapy, veterinary oncologists know just the right dose and regimen to keep patients free of major chemotherapy side effects.

A Drug Just for Dogs

Until now, all the drugs used by veterinary oncologists to treat canine lymphoma were adopted human lymphoma drugs. Recently, however, the FDA approved rabacfosadine, the first drug specifically for the treatment of lymphoma in dogs. Dr. Brenda Phillips, a board certified veterinary oncologist in San Diego, was one of the investigators involved in the clinical trials that led to approval of this new drug. Dr. Phillips' comments probably sum up the opinion of many veterinarians with lymphoma patients when she points out that, “I for one, am very excited that Tanovea™-CA1 (the trade name of the new drug) will soon be available for the treatment of canine lymphoma. Veterinarians can prescribe the drug as first-line chemotherapy or in dogs with relapsed lymphoma.” The drug, which must be administered intravenously, is now available to veterinarians who treat lymphoma and will be an important advance both for dogs suffering from lymphoma and their families. Veterinary oncologists like myself anticipate that having an additional drug that's effective against lymphoma will improve survival times and keep dogs and their families together longer.

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