The doctors and nurses at Hope Veterinary Specialists understand the emotional impact that a diagnosis of cancer in your beloved pet may have on your family.
Our team of specialists offers compassionate and quality healthcare to our patients. We treat all types of cancers, and our primary focus is on maintaining and improving your pet’s quality of life throughout treatment. We are committed to finding the right combination of personalized cancer treatments for each patient.
The Hope VS oncology team uses a multidisciplinary approach that includes chemotherapy, radiation therapy, immunotherapy, and clinical trials evaluating cutting-edge therapies. Our team of doctors includes board-certified surgeons who specialize in surgical oncology and minimally invasive surgical techniques. Our medical and radiation oncologists provide consultation, diagnosis, and treatment planning for all cancer types and they have extensive training and over 20 years of combined clinical experience in cancer biology, chemotherapy, immunotherapy, and novel therapeutics. Veterinary nurses with extensive training and experience in chemotherapy support the oncology team and provide compassionate care and treatment to our patients with cancer.
Alternative therapies, such as polysaccharopeptide (PSP), are sometimes used in place of or in conjunction with your pet's standard cancer treatments. PSP is the bioactive agent from the mushroom Coriolus versicolor, which has been used in traditional Chinese medicine for more than 2,000 years. Some studies have indicated that PSP has in vitro anti-tumor activities and inhibits the growth of tumors in animals.
A study published by University of Pennsylvania researchers evaluated a mushroom extract in a small number of dogs with naturally occurring hemangiosarcoma, an aggressive, invasive cancer that arises from the blood cells and typically affects the spleen. Patients in the study received the mushroom extract as the sole therapy without surgery. Results suggested that the mushroom extract was helpful in fighting the tumors. Further investigations on a larger scale are currently underway. Hope Veterinary Specialists oncology service doctors are currently evaluating this compound and are collaborating with the Veterinary Clinical Investigations Center at the Matthew J. Ryan Veterinary Hospital of the University of Pennsylvania in Philadelphia in a clinical trial evaluating dogs with hemangiosarcoma treated with one of three options:
- The mushroom extract alone
- The mushroom extract in combination with chemotherapy
- Chemotherapy alone
Hope VS is the only center outside of the University of Pennsylvania participating in the trial.
Chemotherapy is one of the standard therapies used to treat cancer. The goal of chemotherapy is to control or eliminate the cancer while maintaining the highest quality of life for your pet. Chemotherapy drugs help control the cancer by killing cells and preventing their growth and ability to divide and spread. Unlike humans, the side effects of chemotherapy in pets are relatively mild and most pets maintain an excellent quality of life.
Your pet will be treated using a specific “protocol,” which refers to a set of specific drugs given in a specific sequence and over a specific time frame. Your pet's oncologist will calculate the most appropriate drug doses and treatment schedules to effectively fight the cancer while minimizing any discomfort to your pet. Drugs may be given daily, weekly, or every 2 to 3 weeks. Some chemotherapy drugs must be given directly into the vein (intravenously). Others may be administered under the skin (subcutaneously) or into a muscle (intramuscularly). In some cancers, chemotherapy may be injected directly into the tumor itself.
Many chemotherapy protocols involve a series of treatments, followed by a monitoring period with scheduled recheck examinations with your pet's oncologist. He or she may change your pet's chemotherapy protocol during treatment to achieve the best outcome. A multimodality approach that includes surgery, radiation therapy, chemotherapy, immunotherapy, and alternative therapies may also be used, similar to how cancer is treated in people.
When your pet is diagnosed with cancer, you may feel overwhelmed with questions and concerns about chemotherapy and radiation treatment. To help answer your questions and allay your fears, our experienced oncology team at Hope Veterinary Specialists has created the following FAQ of common misconceptions about cancer treatment.
I’ve heard that chemotherapy will cause significant side effects causing my pet to become sick.
The majority of pets tolerate chemotherapy very well. Approximately 90 percent of pets receiving chemotherapy never experience side effects. Five to 10 percent of pets experience mild, transient side effects that resolve without intervention after 1 to 2 days. These side effects include mild stomach upset and soft stool. Rarely, some pets receiving chemotherapy experience more serious side effects that require fluids and anti-nausea medication. These more serious side effects are rare and occur in less than 3 percent of pets receiving treatment. Our goal in veterinary oncology is not only to control the cancer but also to improve the quality of the pet's life. Pets receive a lower dose of chemotherapy than people undergoing chemotherapy and, as a result, tolerate chemotherapy better than people. The majority of pet owners agree that chemotherapy treatment helps make their pet feel better.
I’ve heard that certain things, such as food, can contribute to the development of cancer.
Foods do not typically cause cancer unless they are contaminated with cancer-causing agents called carcinogens. Cancer is more likely to be caused by genetic factors, environmental contaminants (i.e., pollution and smoking), hormonal influences (e.g., not spaying female dogs and cats), a compromised immune system, inflammation, and long term use of immunosuppressant medications.
I’ve heard that my pet will lose his/her hair while undergoing chemotherapy treatment.
Complete hair loss (alopecia) is not a typical side effect of chemotherapy for most dogs and cats. Alopecia tends to occur only in breeds of dogs that have hair rather than fur, for example, the Bichon Frise, Poodle, and Maltese. Most dog breeds, such as Golden Retrievers, Labrador Retrievers, and Shepherds, have fur rather than hair and may experience increased shedding but not alopecia. Both dogs and cats may lose whiskers during chemotherapy. Alopecia and/or whisker loss does not affect your pet's quality of life as these changes are only aesthetic. Once chemotherapy treatment is completed, the fur and/or whiskers will grow back depending on the timing of the hair's growth cycle.
Will I have to isolate my pet from the rest of the family and other pets during his/her cancer treatments to avoid my family from getting exposed?
You do not need to isolate your pet while he or she is undergoing treatment for cancer. We do, however, recommend that you follow standard hygienic practice when cleaning your pet’s eliminations. Use gloves or a paper/plastic bag when handling urine and feces. Clean the litter box and/or pick up eliminations in the yard frequently. Always wash your hands after handling pet waste.
My pet is too old to handle chemotherapy treatment.
Age does not affect the ability of your pet to tolerate cancer treatment. As long as he or she is otherwise healthy, your pet can receive chemotherapy. Side effects are typically rare and mild when they occur.
My pet will be radioactive following radiation therapy.
Radiation therapy does not cause your pet to emit radioactive particles. You can continue to enjoy your pet's company as you would normally following treatment.
I’m afraid that my pet will spend a majority of the time in the hospital receiving treatment and that my own schedule will not enable me to continuously bring my pet for treatments.
At Hope Veterinary Specialists, most chemotherapy treatments are performed on an out-patient basis, and the average length of treatment is 1 to 2 hours. Depending on the protocol, injectable treatments may be administered once a week or once every 2 to 3 weeks. Some protocols involve the use of chemotherapy pills, which are administered at home, but you may be required to have your pet's blood tested at regular intervals--this can sometimes can be performed by your primary veterinarian. Because we strive to accommodate your schedule as much as possible, our oncology service is available 6 days a week, generally from 8 am to 5 pm. You can also drop off your pet for treatment at Hope VS for any portion of the day at no additional cost, and we offer chemotherapy services at 2 other area hospitals (near Allentown, PA and Lancaster, PA) that may be closer to your home.
If my pet goes into remission with the first few treatments, why does he or she need to continue receiving chemotherapy?
Generally, cancer is not a curable disease. Microscopic cancer cells can continue to travel throughout the body even when a pet enters remission. Chemotherapy has a better chance of finding and destroying microscopic cancer cells when it is continued for a specific timeframe and at a designated frequency. If treatment is stopped prematurely, these microscopic cancer cells may find a new location in the body to grow and may even become stronger or replicate more quickly. These cells can also become more resistant to the drugs given during treatment, which can reduce or eliminate their effectiveness if used again.
Immunotherapy is a type of treatment designed to stimulate or suppress the immune system to help it fight diseased cells (eg, cancer) and infectious agents. Most immunotherapies are designed to stimulate the immune system, which is designed to recognize the body's own normal cells (ie, red blood cells, white blood cells, and all other cells that an individual is born with) as "self" and non-threatening and foreign cells (ie, viruses, bacteria, and parasites) as "non-self" and dangerous. Because cancer cells originate from normal body cells, the immune system often does not recognize them as "non-self," which allows them to replicate out of control.
The ideal cancer immunotherapy agent stimulates the immune system to discriminate between cancer and normal cells and is potent enough to kill small or large numbers of tumor cells and prevent recurrence of the tumor. One example is the canine melanoma vaccine, which is the first commercially available vaccine for the treatment of canine melanoma. This innovative DNA-based cancer vaccine has significantly improved the lifespan of dogs that have received it, even those already diagnosed with melanoma. Since receiving full government approval in 2009, ONCEPT, produced by Merial, has been shown to be a safe and effective adjunct therapy for dogs with canine melanoma.
Immunocidin is another type of immunotherapy treatment that utilizes a specific, non-infectious portion of a bacteria called Mycobacteria to stimulate the immune system to produce mediators with anticancer effects. Immunocidin is used to treat canine mammary cancer and typically is administered directly into the tumor. Sedation or anesthesia may be required for treatment as the injection may cause some discomfort. Immunocidin has a low risk of allergic reaction, however. Recent data presented at the Veterinary Cancer Society Meetings showed positive results when Immunocidin was used in patients after surgical removal of their tumors.
Some cancers suppress the immune system, so another immunotherapy strategy is to remove this effect. An immune system cell called the T-regulatory cell suppresses the immune system when stimulated by cancer cells, enabling cancer cells to evade detection. Continuous, low dose (or metronomic) therapy with certain oral immunotherapy agents removes T-regulatory cells from circulation, which makes it easier for the immune system to recognize cancer cells.
Traditionally, chemotherapy has been delivered at maximally tolerated doses intended to maximize the destruction of rapidly dividing cells such as cancer. Some normal cells in the body also divide rapidly, however, and may be killed by chemotherapy. To minimize the effects of normal cell death, chemotherapy drugs are typically stopped for a period of time to allow patients to recover. Unfortunately, this recovery period may also provide time for the cancer to rebound.
Currently, a different approach to chemotherapy is being studied. This is referred to as “metronomic” or continuous, low-dose chemotherapy, which targets the blood vessels that provide oxygen and nutrients to a tumor. As tumors enlarge, they require a greater blood supply, which is delivered by new blood vessels formed in a process called angiogenesis. In angiogenesis, tumors send signals to nearby blood vessels, which induces new blood vessels to form and grow toward the tumor. Once this connection is established, the tumor receives oxygen and nutrients from the blood, enabling further tumor growth and spread. These blood vessels are sensitive to extremely low dosages of chemotherapy, however, so when chemotherapy is given chronically, the blood vessels stop growing and can be pruned away from the tumor, resulting in decreased tumor growth and ultimately, tumor death. A metronomic protocol typically involves daily administration of a chemotherapy drug at a low dose in conjunction with a nonsteroidal medication, for example, cyclophosphamide and piroxicam, meloxicam, or deramaxx.
The goal of metronomic chemotherapy is to stop a tumor from growing and spreading, not to eliminate it completely, while limiting side effects. These medications are given orally so they may be administered at home. Several veterinary studies have noted positive responses to metronomic chemotherapy used to treat bulky cancers alone or prior to surgery and to treat tumor roots left behind following surgery.
During metronomic chemotherapy, patients require regular physical examination and laboratory testing of blood and urine samples. Metronomic therapy can be combined with standard chemotherapy or radiation therapy and provides another therapeutic option for patients with cancer.
When your pet is diagnosed with cancer, we understand that you want to learn everything you can about it, and that you may have financial concerns about the cost of treatment. To help you find additional information, our oncology service recommends the following websites:
- Tripawds (http://tripawds.com/) is a resource for owners of dogs and cats that have lost a leg. It provides a community where you can share your pet's story and learn from others about amputation, canine osteosarcoma or other cancers, and loving life on three legs.
- Magic Bullet Fund (http://www.themagicbulletfund.org/) helps clients who cannot afford cancer treatment for their canine companion.
- Emma's Foundation for Canine Cancer, Inc. (http://emmasfoundationforcaninecancer.org/) helps increase awareness about canine cancer and provides resources and financial support to pet owners who cannot afford the cost of canine cancer treatment for their beloved pet.
If you do not find what you are looking for here, please let us know!
Tyrosine Kinases and Their Inhibitors
Receptor tyrosine kinases (RTKs) are proteins found on the surface of cells that bind growth factors that circulate in the blood. Under normal conditions, when a growth factor binds to the receptor, this turns on signals in the cell that promote cell growth, cell survival, the ability to move and spread. When the receptor is located on a blood vessel cell (endothelial cell) this can lead to angiogenesis (development of new blood vessels). Examples of surface RTKs include Kit, epidermal growth factor receptor (EGFR), vascular endothelial growth factor receptor (VEGFR), and platelet-derived growth factor receptor (PDGFR).
In some tumors, cell signaling through receptor tyrosine kinases is disrupted because of genetic changes (called mutations) in the receptors on the surface of the tumor cells, overexpression of these receptors, or co-expression of receptor and growth factor. The consequence of this dysregulation is persistent cell signaling, which leads to uncontrolled cell proliferation and survival.
Many well-characterized examples of RTK dysfunction now exist in human and veterinary medicine. Perhaps the most studied example in veterinary medicine is the presence of Kit mutations in 20 percent to 40 percent of dogs with mast cell tumors. Abnormal function of the VEGF and PDGF receptors is likely to be present in a variety of canine and feline cancers, including feline injection site sarcomas, osteosarcoma, anal gland carcinoma, squamous cell carcinoma (canine and feline), hemangiosarcoma, thyroid carcinoma, and nasal carcinoma. RTK dysfunction in these cancers promotes tumor growth and progression.
Receptor tyrosine kinase inhibitors (RTKi) are a class of drugs that bind receptor tyrosine kinases and prevent the initiation of receptor signaling that would otherwise promote cell growth and survival. In veterinary medicine, the drug toceranib phosphate (Palladia; Pfizer Animal Health) is fully approved by the FDA for the treatment of cutaneous mast cell tumors. This drug inhibits several RTKs including cKit, PDGFR, and VEGF. Studies have demonstrated that response to Palladia occurs in approximately 40 percent of all dogs with mast cell tumors and greater than 70 percent of dogs with KIT mutations. This drug has also been shown to be effective in the treatment of various other cancers, including thyroid carcinomas, nasal carcinomas, anal sac tumors, and head and neck carcinomas.
In addition to Palladia, studies are currently underway evaluating the usefulness of several similar medications in treating a variety of tumor types. Because of their novel mechanism of action in attacking cancer cells, they can be used with our current standard therapies, which consist of surgery, radiation therapy, and chemotherapy.
- London CA et al. Phase I dose-escalating study of SU11654, a small molecule receptor tyrosine kinase inhibitor, in dogs with spontaneous malignancies. Clin Cancer Res. 2003; 9:2755-2768.
- London CA, Malpas PB, Wood-Follis SL, et al. Multi-center, placebo-controlled, double-blind, randomized study of oral toceranib phosphate (SU11654), a receptor tyrosine kinase inhibitor, for the treatment of dogs with recurrent (either local or distant) mast cell tumor following surgical excision. Clin Cancer Res. 2009, 15:3856-3865.
- London CA, Mathie T, Stingle N, Clifford CA, Haney S, Klein MK, Beaver L, Vickery K, et al. Preliminary evidence for biologic activity of toceranib phosphate (Palladia®) in solid tumours. Vet Comp Oncol. 2012;10:194-205.
- Carlsten KS, London CA, Haney S, et al. Multicenter prospective trial of hypofractionated radiation treatment, toceranib, and prednisone for measurable canine mast cell tumors. J Vet Intern Med. 2012;26:135–141.
- London C, Gardner H, Mathie T, Stingle N, Portela R, Pennell M, CA Clifford, et al. Impact of toceranib/piroxicam/cyclophosphamide maintenance therapy on outcome of dogs with appendicular osteosarcoma following amputation and carboplatin chemotherapy: a multi-institutional study. Plos One. 2015; 10:e0124889.
- Burton, JH, Venable RO, Vail DM, Williams LE, Clifford CA, et al. Pulse-administered toceranib plus lomustine for the treatment of unresectable canine mast cell tumors. JVIM. 2015;29:1098–1104.
- Gardner HL, London CA, Portela RA, Nguyen S, Rosenberg MR, Klein MK, Clifford CA, et al. Maintenance therapy with toceranib following doxorubicin- based chemotherapy for canine splenic hemangiosarcoma. BMC Veterinary Research. 2015;11:131.
Surgical oncology focuses on the surgical management of cancer. At Hope Veterinary Specialists, our surgeons have expertise and experience using minimally invasive techniques, palliative surgery, and neo-adjuvant therapy to treat your pet's cancer. Surgery may be combined with chemotherapy, radiation, and targeted biologic therapy as part of our team-based approach to your pet's treatment.
The US Food and Drug Administration recently announced that it granted conditional approval for the first new animal drug to treat canine lymphoma. The FDA said the active ingredient in Tanovea-CA1 is rabacfosadine, a substance that kills rapidly growing cancer cells.
Tanovea-CA1 must be prescribed by a licensed veterinarian because professional expertise is needed to correctly diagnose lymphoma in dogs, determine the best treatment, and manage potential side effects. Tanovea-CA1, which comes in a concentrated form, is diluted and given in a vein over 30 minutes. The infusion should be given by or under the supervision of a veterinarian experienced in chemotherapy.
The “CA1” in Tanovea-CA1 means the drug is conditionally approved. Only animal drugs intended for minor species, such as ferrets or fish, or for minor uses in a major species, such as to treat certain types of cancer in dogs, are eligible for conditional approval. Tanovea-CA1’s conditional approval means that when used according to the label, the drug is safe and has a “reasonable expectation of effectiveness” for treating lymphoma in dogs.
At Hope Veterinary Specialists, our oncology service is excited to add this agent to our current list of drugs to treat lymphoma. We have been using this drug as part of clinical trials for the past several years and have treated more than 150 patients. If you have any questions regarding the drug or patients that may be eligible, please contact us at 610.296.2099 or [email protected]
ONCOLOGY APPOINTMENT DAYS
To schedule an oncology appointment, or to talk to an oncology specialist, please call us at 610.296.2099