The Dog Cancer Survival Guide (93 page)

The conventional treatments that Dr. Ettinger recommends for lymphoma may be considered part of step one of Full Spectrum cancer care (
Chapter 11
). Please review that chapter for more general information about surgery, radiation and chemotherapy and handling their common side effects.

For more information on all other Full Spectrum steps, including nutraceuticals, immune boosters, dietary changes and brain chemistry modification strategies, review Full Spectrum cancer care, which begins on
page 103
.

You will also find information about specific chemotherapy agents in
Chapter 41
.

During most CHOP protocols (including the UW), dogs get weekly treatments. Depending upon the specific version of the protocol chosen, treatments may decrease in frequency to every other week. Lymphoma typically responds quickly to treatment, so most dogs who are sick at the time of diagnosis are feeling better, or even back to normal, within two to fourteen days of the first session.

Given the number of treatments and how many agents are involved, CHOP protocols are some of the costliest lymphoma treatments available.

Your oncologist may outline alternative lymphoma protocols, some of which may be less expensive and require fewer visits than CHOP. As usual, there are trade-offs to consider when looking at other options.

One protocol I offer is the single-agent doxorubicin protocol. This protocol has a 60-80% response rate (compared to 90% with the UW CHOP) and median survival times of seven to nine months (compared with thirteen to fourteen). As there is also a potential for cardiotoxicity (heart problems) after six to eight doses of the doxorubicin, oncologists typically stop treating with this agent after five or six doses.

Some of my clients choose the COP protocol (cyclophosphamide, vincristine or Oncovin, and prednisone). The complete remission rate is about 70%, with a seven-month median survival time. In the first six months, this protocol is certainly less expensive than the twenty-five-week UW CHOP protocol. Treatments continue during remission. If the dog stays in remission for a year (which of course makes us happy), the cost, over time, may actually exceed that of the UW CHOP protocol. Some clients prefer that the cost and the visits are spread out, while others wish they had gone with the UW CHOP to begin with, so that their dog could have had more intense treatments up front, yet enjoyed more treatment-free time in remission.

While chemotherapy is the treatment of choice, there are a few other treatment options.

Prednisone is a steroid often prescribed for its anti-inflammatory effects. However, it also has anticancer properties, and can help kill some of the lymphoma cells. The complete remission response rate is only 50%, much lower than those of the chemotherapy protocols mentioned above, and the median survival time is two to three months. Nevertheless, prednisone helps the dog feel better, and steroids are very inexpensive. Because prednisone can interfere with chemotherapy if started prior to treatments, using it is not recommended unless chemotherapy has been totally eliminated as an option.

If radiation is available in your area, palliative radiation can be useful in treating lymphoma, especially when it is directed at a single area, to relieve symptoms associated with an obstruction. For example, if a lymph node under the jaw is very swollen and large, it can obstruct the upper airway and impede breathing and/or swallowing. Radiation can reduce the size of the lymph node and ease these symptoms, markedly improving the quality of life. Palliative radiation can also ease breathing, by shrinking a swollen mediastinal lymph node in the chest cavity. In another example, if spinal lesions are pressing on the spinal cord, there can be symptoms like pain or paralysis. In these cases, palliative radiation can shrink those lesions and help improve symptoms. Palliative radiation protocols for lymphoma typically require four to six weekly treatments and should be used in combination with traditional chemotherapy protocols.

Another type of radiation treatment is called “half-body” radiation. During this protocol, the dog’s body is irradiated one-half at a time, first from the mid-section up, and then from the mid-section down, without overlapping the treatments. Dogs who receive both this half-body radiation and the standard twenty-five-week UW CHOP chemotherapy survive five extra months (in addition to the thirteen or fourteen from the UW CHOP). However, some oncologists question whether the increased cost and toxicity from the radiation are worth the extra time. Every dog, every cancer and every owner is different, so this is a topic for you to consider and discuss with your oncologist.

You may have heard about a human treatment for lymphoma: a bone marrow transplant with total body radiation treatments to put the cancer into full remission. The goal of this treatment is to cure the lymphoma, and the cure rates in people with Non-Hodgkin’s lymphoma are 50-66%.

This treatment is also offered for dogs, with the same intent to cure. In order to qualify for this procedure, the dog must already be in remission, so most dogs have to get chemotherapy for two to twelve months prior to the treatment. It’s offered at very few places, including North Carolina State University (NCSU).

The first step in the procedure is to give dogs very high doses of chemotherapy to clear lymphoma from the blood. This usually takes two weeks. Next, a medication called Neupogen is given for eight days, which drives healthy stem cells out of the bone marrow and into the bloodstream. After that, a complex series of procedures harvests those healthy stem cells from the blood (this is called leukaphoresis). Once the stem cells are safely out of the body, the dog is given total body radiation to kill all the lymphoma cells. This is a very intense procedure, lethal to more than 95% of dogs if they do not receive a bone marrow transplant immediately afterward. During the transplant, the healthy stem cells are re-planted into the bone marrow by transfusion (the stem cells do not have to be implanted directly back into the marrow, they enter the body through a vein). This is done soon as the radiation is complete, in the hope that the marrow will replenish the blood with healthy red blood cells, healthy white blood cells and healthy platelets.

This intense treatment is not for every patient. For one thing, it is very expensive (about $15,000-$17,000, plus the costs of all of the prior chemotherapy treatments) and requires two to three weeks of hospitalization. During this time, dogs must often be in total isolation, because they will temporarily have no white blood cells or platelets, leaving them at risk for infections and bleeding disorders. Also, the toxicity of this protocol varies from manageable to lethal, depending upon the patient. As it is still fairly new, it is too early to know what the cure rate is in dogs, but it could be a good option for the right dog and the right owner. If you are interested, consult with Dr. Steven Suter at NCSU, who has done the most research and treated the most dogs to date.

A good outcome for lymphoma protocols is a four- to six-month complete remission after completing the CHOP chemotherapy. However, relapses can occur. One possible reason for this is that lymphoma cells have become increasingly resistant to chemotherapy agents during the course of treatment (survival of the fittest).

At the beginning of chemotherapy, the cells most sensitive to the agents are the first ones killed. As treatment wears on, however, the remaining cells tend to be stronger and more resistant. These “survivor” cells are more likely to express the gene encoding for P-glycoprotein, which is associated with multi-drug resistance (MDR). You may remember this protein from our discussion about prednisone, above, or from the sidebar on
page 130
. This special protein acts as a pump in the membrane or outer layer of the cell. When chemotherapy agents come in, this protein literally pumps them back out, rendering them ineffective.

“We heard about the stem cell bone marrow transplant program at North Carolina State University and - after doing a lot of soul searching - decided to make the commitment so LP could have a chance for a longer life. While LP was there for three weeks, we also used so many things we had learned in your book and found the staff at NC State so accommodating. They were so open minded about LP’s diet and even have a nutritionist who worked with us. They have one person who spent time just sitting with LP during the extended time when we couldn’t see him. I stayed in Raleigh for a couple of weeks and kept doing my visualization exercises and I am sure it helped LP and me. My husband is an equine vet and we deal with vet schools all the time. North Carolina State University is a very special place that we both highly recommend.”

- Susie, Millwood, Virginia