A Treatment Option for Canine Cancer

SheltieJane and Jim Lewis of Cheyenne, Wyoming, are active retirees who regularly walk two to four miles with their beloved rescue dog, an 11-year-old Shetland Sheepdog named Sassy.  The Lewis’ adopted Sassy when she was a three-year-old, obese throw-away pet whose former owners dropped her off and never looked back.  Lucky for Sassy, her new owners dote on her.  One day in May 2012 when Sassy was age 10, the Lewis’ noticed some small growths on her spine, so they took her to see Veterinarian Dr. Rod Hartshorn of the Avenues Pet Clinic.  Dr. Hartshorn biopsied Sassy’s lumps; unfortunately, the report was grim.  She had four to six weeks to live.

Sassy’s diagnosis revealed cutaneous lymphoma, a form of cancer derived from white blood cells called lymphocytes.  Jane and Jim Lewis were devastated by the news, but fortunately Dr. Hartshorn offered a glimmer of hope.  It just so happened that only 40 miles away in Fort Collins, Colorado, the Animal Cancer Center at Colorado State University (CSU) was conducting a clinical trial to study Sassy’s type of cancer.  The Lewis’ jumped at the opportunity to help their treasured friend, so Dr. Hartshorn arranged for Sassy to be screened as a potential candidate.

What is a clinical trial?  Simply put, it’s a scientific study which relies on volunteers– namely, pets that are enrolled by their owners– to test new or refined medications or medical procedures.  According to the National Institutes of Health, “In a clinical trial, participants [the dogs] receive specific interventions according to the research plan created by the investigators.  These interventions may be medical products  such as drugs, devices, or procedures.  Clinical trials may compare a new medical approach to a standard one that is already available or to a placebo that contains no active ingredients.  When a new product or approach is being studied, it is not usually known whether it will be helpful, harmful, or no different than available alternatives (including no intervention).  The investigators try to determine the safety and efficacy of the intervention by measuring certain outcomes in the participants.”

Dr. DoThammuglas Thamm, VMD, DACVIM, an oncologist at the CSU Animal Cancer Center, says that clinical trials are conducted in four distinct phases.  He explains, “In Phase One, researchers test a new drug, drug combination or treatment in a small group of patients, often with different types of cancer, to evaluate safety, determine safe dosage ranges, and identify side effects.  Typically, a very low dose of a new drug is administered, and if there are no side effects, that dose is gradually increased in additional patients.

“In Phase Two, the new drug or treatment is give to a larger group of patients, usually with the same type of disease, to see if it is effective and to further evaluate its safety.  During Phase Three, the new drug or treatment is give to still larger groups of patients to confirm its effectiveness, monitor side effects, compare it to commonly used treatments, and collect information that will allow the treatment to be used safely.  These trials are usually necessary for regulatory approval by the FDA or USDA.  Finally, Phase Four trials are post-marketing studies that delineate additional information including risks, benefits, and optimal use.”

Sassy would be enrolled in a Phase Two trial if she passed the screening tests.  Her owner, Jane Lewis, recalls, “We took her to CSU, and they [the veterinarians] tested her health which was fairly good except for the cancer.  They verified the previous tests for cancer, concurred on the diagnosis, accepted her into the trial, and began treatment.  When she was examined, a group of veterinary doctors and students clustered around, checking her and explaining the process.  They said that the drug they would use would probably make her ill at times, and the prognosis was not guaranteed.  They promised no cure, only that they would administer the drug, constantly test her condition, and keep us advised.”

Obviously, clinical trials exist because the drugs or procedures being evaluated are unproven, so there are precautions to consider.  Dr. Thamm states, “Some clinical trials that involve simple procedures such as blood collection or special handling of tissues to be removed at surgery may be appropriate for any dog with cancer.  However, participation in therapeutic trials with new drugs or treatments, especially early phase trials, needs to be considered more carefully, as the effectiveness of these treatments is generally not well known, and potential toxicity may not be as well established.”  Nevertheless, there is always a risk involved with any medical procedure, experimental or otherwise, so Dr. Thamm advises pet owners to focus on the research practitioner’s standard of care to insure that every effort will be made to provide the highest quality therapy.

Another important consideration is whether pet owners can meet the requirements of the study.  For example, owner compliance with regard to scheduled appointments, pre- and post-operative care, and administration of medication is paramount to the success of the trial and to the status of the patient’s health.  Therefore, owners must be certain that personal and career obligations will not interfere.  The Lewis case is a perfect example of ideal participants because the owners are retired, they live near the research facility, and they are committed to their pet’s care.

Admission into an investigative program requires volunteers to accept the precautions associated with an unproven therapy.  On the other hand, the benefits of inclusion are equally important.  For example, a primary advantage is cost savings.  Obviously, cancer is an expensive disease, and the financial burden of a pet’s illness may dictate whether or not owners can even consider pricey interventions.  However, since research studies often provide discounts or incentives, treatment may be viable for owners who otherwise would have to forego it.  Dr. Thamm agrees.  He says, “Participation in a clinical trial may mean the difference between a pet receiving an investigational therapy or no therapy at all.”

Another distinct advantage to inquiry-based treatment is the opportunity for pets to profit from cutting-edge science.  Obviously, the goal of research is to make medical advances.  In order to do so, scientists must have access to the latest technology on the market, and they must receive advanced training for optimal use of such equipment.  As a result, clinical trials provide ailing pets with access to highly trained personnel and the most up-to-date diagnostic devices available.

So how do owners go about finding clinical trials?  According to Dr. Thamm, “There are multiple websites [see below] that list ongoing clinical trials for pets with cancer.  The most frequently updated and comprehensive is the site managed by the Veterinary Cancer Society.  However, since the majority of clinical trials are conducted at veterinary teaching hospitals associated with universities, making contact with the newest facility may provide a simple way to find out about trials in your area.”  he reminds potential participants that location is a key factor when considering the clinical trial option, since owners must routinely transport their pets for monitoring.

Finally, there are times when medical intervention may not lead to remission but instead provide pets with high quality supportive care and owners with the chance to benefit the greater good.  “Clinical trials can improve an animal’s level of comfort and quality of life during illness, while giving owners the satisfaction of partnering with scientists to afford them hands-on opportunities to gain critical information about the diseases they are committed to conquering.  Hopefully, future generations of pets and their owners won’t have to endure cancer as a result,” says Thamm.

Jane and Jim Lewis claim they were not optimistic upon commencement of Sassy’s treatment.  “We fully expected a short time before she had to be put down,” Jim says.  However, he and his wife continued to garner faith in Sassy’s team of doctors.  “We took her to CSU monthly for her chemo, which they injected into her skinny front legs,” he recalls.  “The chemo made her ill at times, and she had diarrhea and vomiting.  They gave us drugs to combat these problems.  It was seemingly a long, tedious process.”

However, the journey was worth it.  “The growths slowly decreased in size,” says Jane, “and finally the doctors said she was getting better.  She kept on improving, and they stopped the chemo.  She continued improving, and all drugs were discontinued.  They have pronounced her ‘in remission,’ wonderful words to hear.  She is now back to normal and very sassy and spunky for an 11-year-old dog.  She goes on walks with us, with no bad effects, and she does not get very tired.  All effects of the cancer and drugs seem to be long gone.  She returns to CSU for monthly check ups per our agreement.”

For pet owners considering clinical trials, it’s wise to consult their own veterinarian before pursuing any course of action.  However, in the end, owners must choose the path that brings them the most peace of mind while giving their pets the best chance to remain by their sides for as long as possible.

Jane and Jim Lewis proclaim, “The doctors and students at CSU are a group of concerned angels.”  Surely, the Animal Cancer Center was the second divine intervention in Sassy’s life, made possible only because the Lewis’ were the first.

Web Resources for Clinical Trials

There are many websites devoted to clinical trials for pets.  Here are some examples (in alphabetical order):

American Kennel Club Canine Health Foundation

Canine Comparative Oncology and Genomics Consortium

Comparative Oncology Trials Consortium

Morris Animal Foundation

National Cancer Institute Center for Cancer Research

National Veterinary Cancer Registry

Veterinary Cancer Society

A complete list of veterinary schools in the U.S. to inquire locally about possible research in your area

Dr. Thamm’s page at the Colorado State University Animal Cancer Center

Lori Mauger, freelance writer

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