By L.J. Hodek-Creapeau, Circkles Managing Editor
Every time I turn around, someone, or some pet, is diagnosed with cancer. The more shocking side of this tragedy is how we humans just take the cancer statistics in stride like they are a normal part of living. Cancer is not normal. In fact, it is an indication of just how abnormal our living conditions are. If we and our pets are developing cancer at astonishing rates, and we are, that should tell each and every one of us that something is drastically wrong with our lifestyle; namely our food, water and air supply. However, that is a whole different article, for our Green Circles section perhaps.
So, invariably, you will have a pet at least once in your lifetime, and probably more frequently than that, that will end up with cancer. Every pet owner I have ever encountered has a very difficult time trying to decide if they should treat their pet for cancer or have them euthanized. Part of this is a personal decision and nobody can help you with that, but part of it can be approached from a logical and realistic point of view as well.
For instance, there are many factors to consider, pros and cons to weigh, that may help you make your decision whether to try chemo or end your pet’s suffering before spending thousands of dollars on treatments that only have a 40% chance of actually stopping the cancer and prolonging your pet’s life beyond just an additional couple of months.
One veterinarian sums up the conventioanl thought behind this dillemma:
“Which, in case you’re wondering, I can totally get behind. I wholly comprehend the sentiment that says, “I do not want my pet to suffer any more than he has to now that he’s been diagnosed with a terminal disease. The trouble, however, is that most pet owners who reject chemotherapy on these grounds have a mistaken notion of what it is that veterinary chemotherapy is designed to do.
I know this to be true because almost no owner is immediately prepared to euthanize their pet at the time of the cancer diagnosis. What they invariably ask for once the spectrum of treatment options have been discussed and discarded is “just something to make her feel better, Doc.” Which is exactly what veterinary chemotherapy is for.
So the goals for treatment are very, very different, I tell my clients. Chemo for pets is designed to elicit only minimal side effects, so that if patients do start to suffer uncomfortable symptoms we can terminate the treatment. In that way it’s almost exactly what our clients asked for in the beginning: “something to make her feel better.”
Now if it’s this latter rationale, then I can absolutely, unreservedly get behind it; which is why it’s too bad that my patients’ treatment options are so inextricably intertwined with their owners’ concern with what it’ll cost to make them feel better. In a perfect world, teasing out the role of physical welfare versus cost in a client’s mind shouldn’t be my first order of business when a suffering patient sits before me. And yet, it almost always is.”
While this is just one veterinarians opinion, and you should know, it was hit with much criticism from reader comments, it is the biggest decision and most stressful concern to a pet owner when they hear the dreaded words that their pet has been diagnosed with cancer.
Types of Cancer Treatments.
Surgery: Surgical removal of tumors is a very common and valuable approach for solid tissue tumors. It can be used for soft tissue as well as for bone tumors. It can sometimes be curative on its own, if the disease process is localized and detected very early.
Radiotherapy: Or “radiation” therapy is available at large veterinary institutions such as Tufts University School of Veterinary Medicine (North Grafton, Massachusetts) and Angell Memorial Animal Hospital (Boston, Massachusetts). It consists of the use of a radioactive beam to damage and/or kill malignant cells in a localized area. It can offer good quality remission times for many types of tumors, but usually not cure. Animals are surprisingly tolerant of radiation therapy
Chemotherapy: Is the use of certain drugs alone, or in combination to control tumor growth. All of the drugs currently given to animals are human anti-cancer drugs. Fortunately, many of the negative consequences of their use in human medicine are not experienced in veterinary medicine. Chemotherapy and/or surgery are the two most important treatment modalities in veterinary cancer medicine. A combination of therapies may also be indicated in certain cancers. Some cancers require a specific, brief number of treatments, while others requiring ongoing treatment to maintain remission. The word “chemotherapy” usually evokes unpleasant thoughts in most peoples minds. We prefer to think of it as “therapy” for a disease, in the same way people take medications for certain illnesses. The ultimate goal of therapy would be to cure the patient of cancer. In most instances at this point in time in veterinary medicine, this goal is not realistic. The goal we do strive for is to control rapidly progressive disease, prevent spread of the tumor, restore deteriorated function, and provide a good quality of life during the time of remission. The term “remission” means a time interval during which there are no outward signs that the patient has cancer.
Most Common Forms of Pet Cancer.
Lymphoma: The average survival of lymphoma with chemotherapy is about 10-12 months. In the case of lymphoma, if the maximum combination protocol is used, it is expected that 80% or more of patients will go into full remission. The average duration of remission is longer than 12 months. Unfortunately, it is impossible to predict which animals will achieve a full remission or for how long. We do know, however, that if no therapy is used, most pets will die from their disease in a few days to a few weeks.
Behavior & Treatment:
Osteosarcoma is the most common primary bone tumor of dogs. Large and giant dog breeds are at highest risk of this malignancy. This tumor is locally destructive to normal body tissues, and has a high metastatic rate (tendency to travel to distant sites in the body). It is one of the cancers in dogs that can be painful when it is in its active stages. Bones of the limbs that are affected by osteosarcoma can be weakened to the point of a fracture (called a pathological fracture).
If no treatment is rendered, the animal usually succumbs to the disease within 1-2 months from the time of diagnosis. Surgical resection of the tumor and/or limb amputation are key to treatment of osteosarcoma. Though many owners are at first hesitant about surgery, they frequently observe that their dogs improve dramatically after this treatment. This is by and large because a source of constant pain has been removed. It is important to note, however, that surgical resection alone does little to prolong the dogs survival time.
What about chemotherapy?
Osteosarcoma is always considered to have spread microscopically in the dogs body by the time the diagnosis is made. This is the reason that surgery alone fails to control the disease. To attack the cancer cells both locally and systemically, chemotherapeutic agents can be used. The goals of therapy are to preserve a good to excellent quality of life for the dog, eliminate pain, and provide as long a remission time as is possible. Cure is not a reasonable goal at this time, and this fact must be realized by the owner prior to initiating therapy.The two most common chemotherapy agents used for osteosarcoma are Adriamycin® and platinum compounds such as Carboplatin or Cisplatin. Because Adriamycin® and Carboplatin are synergistic with respect to their anti-cancer activity, they are often alternated in treatment protocols. Treatments are done as outpatient visits, every 3-4 weeks, for a total of 4-6 treatments. The actual treatment time takes approximately 30 minutes.
As previously mentioned, a dog that is given no treatment, or treatment with surgery alone is expected to live 1-2 months from the time of diagnosis. However, for a dog that undergoes surgery plus adjunct chemotherapy, the expected 1 year survival rate is 50%, the 2 year survival rate falls to about 20%. The cancer eventually starts to grow in the lungs which leads to coughing, weight loss, and malaise.
Adriamycin is a potent anti-cancer drug used in both humans and animals for many different types of cancers. It has been shown to be beneficial in treating canine osteosarcoma, but is best used with a platinum compound. Occasionally, nausea and vomiting can occur within 2 days of administration of the drug. These episodes are infrequent and can usually be mitigated by using anti-nausea medications. The most serious side effect results from the dogs white blood cells being lowered (infection fighting cells). This usually occurs about 5-8 days after treatment. Symptoms include sudden lethargy, refusal to eat, reluctance to rise, and fever. If this happens, follow the directions you have been given and/or call the hospital ASAP. This side effect can be rapidly and successfully treated. However, ignoring these important signs can be lethal!
Carboplatin is the “gold standard” in treating canine osteosarcoma. It is useful as a single agent, or in combination with Adriamycin®. Carboplatin occasionally causes dogs to act “subdued” or have a decreased appetite for 2-3 days after administration. This effect tends to be mild. Carboplatin, like Adriamycin®, has a tendency to lower the white blood cell/platelet counts. This is less common and usually less severe than with Adriamycin®. It occurs approximately 10-13 days after administration. This drug could theoretically cause damage to the kidneys over time, but this is very uncommon. Your dog will be monitored for side effects during treatment. Unfortunately, because the “platinum” compounds actually do contain platinum, they are very costly! A cost estimate of treatment will be given to you during your visit.
Quality of life?
Fortunately, most dogs who undergo treatment for osteosarcoma are lucky enough to have an excellent quality of life! They are pain free, and done with treatment after 4-6 rounds (3 week intervals). They rarely have to be hospitalized, so that they can be at home with “their people.” Dogs can continue to do virtually every activity that they are used to doing (yes, even hiking..). We hope to make your dogs remission as long and enjoyable as possible!
What is Life Like for Chemotherapy Patients?
Veterinarians who treat animals for cancer use many of the same chemotherapy agents that human oncologists use. Yet, in many ways the experience for pets seems very different. Why? For one thing, dosages of chemotherapy agents used in animals tend to be much lower than those used in people. Humans are given the highest doses possible, the consequences of which may require bone marrow transplantation, extended hospitalization, and numerous costly medications-all with good cause. However, for veterinary patients, this process would be unacceptable and cost prohibitive for most owners. The general quality of life for many veterinary cancer treatment patients can be surprisingly good and very close to normal. Most of the time they can maintain their normal activities, travel, and have fun with the families that love and care for them.
Most currently used anti-cancer agents do not specifically target cancer cells. Rather, they target and damage or kill rapidly growing cells. For the patient, this means cells lining the stomach and intestine (high turnover rate), cells of the bone marrow that make up the immune system (white blood cells, in particular), and cancer cells. It then is little surprise that the most common side effects of chemotherapy agents include mild to moderate nausea, vomiting, diarrhea, and increased risk of infection. Hair loss, in contrast to humans, is uncommon in dogs and cats on chemotherapy. The good news is that the normal cell lines can almost always regenerate themselves, while the less well organized malignant cells suffer great damage. However, even at higher dosages, microscopic malignant cell clones remain alive, albeit dormant in the body. Eventually these give rise to drug-resistant cell lines. This is the biological basis of recurrent or metastatic cancers.
Visits and Costs.
For a cancer such as lymphoma, therapy involves a significant time commitment on the part of the owner/family. Outpatient visits are generally once weekly for 4 weeks, then every 3 weeks for up to 18 months. However, we make every effort to accommodate the owners schedule, and most visits require 20 to 30 minutes. Many clients like to leave their pet with us temporarily while they go do errands, and you are welcome to do this. You may halt therapy at any time, but we like to have the owner commit to at least 4 weeks, so you will have the benefit of seeing how well a pet can do. Due to the new OSHA hazard laws, and the fact that the animal must make no movement during the intravenous injections, we regret that it is not feasible to have the owner present during the few minutes of chemotherapy injections. Rest assured that your pet will be gently and expertly restrained by the oncology technician and the doctor. Relative to most other treatments in veterinary medicine, chemotherapy is a costly service to provide. The costs reflect the professional time and expertise required, the high costs of chemotherapy agents (the same used by humans), the special equipment and personnel protection required, and the removal of biomedical hazard waste. Realize however, that this therapy is unique in that it can successfully prolong an animals life!
WHAT IS THE ROLE OF IMMUNOTHERAPY?
Immunotherapy (sometimes called biologic therapy) is a form of cancer treatment that is still in its infancy in both humans and animals; however, great strides have been made in the last decade. The assumption is made that the growth of some cancers occurs because of a defect in the animal’s immune system. Had the patient’s immunity been normal, the tumor growth should have been suppressed very early, when only a few abnormal cells were present. For this reason, stimulation of the animal’s immune system may be attempted as a part of cancer therapy, through the use of certain drugs and antibody treatments. For some tumors, monoclonal antibodies have been made that bind to tumor-associated antigens (special proteins) on the surface of the cell, sometimes causing the destruction of the tumor cell directly. These antibodies can also be designed to guide a chemotherapy medication or a radioisotope directly to the tumor, targeting its death. Great strides are being made in immunotherapeutic treatment at cancer research institutions for humans, and it is likely that veterinary oncologists will begin to be able to take advantage of some of these developments in the next few years. Many veterinarians are quickly adopting the “an ounce of prevention” approach. Since cancer rates are so high in pets, many believe the most beneficial approach is to try and prevent a compromised immune system and possible cancer in the first place through improved diet and avoiding chemicals in foods such as preservatives, pesticides etc.
What Many Pet Owners Face:
Heated comments on forums….
“I believe, that every responsible owner, should account for reasonable veterinary expenses. In a case of cancer, the cost of treatment is extremely high, so the question might be “can I afford it” but sometimes “is it worth it”? Implying that you either must be filthy reach, or be ready for financial catastrophe to invite an animal into your home, is a complete nonsense!
Your pet treatment decision is only yours and your family’s, so don’t let anybody bully you or make you feel guilty. Talk to you friends and people that care about you to offer you advise. In such a difficult time when your beloved pet is very ill, you often lack the right perspective.”