Cancer Care for Cats and DogsDecember 12, 2016
What to Expect
A cancer diagnosis in your pet is a frightening experience that can be associated with stress, concern, and anxiety.
Top Five Misconceptions About Veterinary Oncology
Although we use the same drugs that are used in human oncology, the similarities in the chemotherapy experience stop there. Here are some common misconceptions about veterinary oncology that may help with your decision to pursue a specialist’s opinion or treatment.
Misconception #1: Cancer is not treatable in animals.
Truth: Many pets diagnosed with cancer have the potential of receiving treatments aimed at addressing the cancer condition and/or improving and maintaining their quality of life. The extent and duration of a treatment benefit is dependent on many factors including the type of the cancer, the stage of the cancer (i.e. the extent of disease), the available therapies used to treat the cancer, and the individual features of the patient.
Many animals with cancer now can be cured or managed long-term, and this goal should not be overlooked.
Misconception #2: My pet will lose all of his/her hair.
Truth: While there are certain dog breeds and some cats that do show hair loss during chemotherapy, for the most part, this is not common. Hair loss is more common in non-shedding dog breeds (e.q. poodles). If hair loss occurs, regrowth will occur when chemotherapy is stopped.
Misconception #3: My pet will be miserable during chemotherapy.
Truth: The image of human cancer patients experiencing chemotherapy related side effects is not the same for cats and dogs. In general, chemotherapy in dogs and cats is well tolerated. This is in part related to our goal to use protocols that maximize quality of life and the resilience of our pet animals.
Most pets will experience some mild and self-limiting side effects including: decreased appetite, energy, and overall demeanor for 24-48 hours after a treatment. Isolated episodes of vomiting and diarrhea can also be encountered. The risk for more significant side effects includes a 1:10 chance of vomiting and diarrhea characterized by > 3 episodes of vomiting in a 24 hour period or diarrhea that may be profuse or occasionally bloody in nature. A 1:100 chance of life threatening complications primarily associated with white blood cell suppression (neutropenia) and secondary infection can also occur with most chemotherapy.
Dogs and cats that are at a risk for these more severe chemotherapy side effects are typically very lethargic, not eating, dehydrated, weak, and will have a fever. There are some less commonly used treatment protocols where the risk is higher. If you are concerned about your pet’s current clinical status, please contact us or have your pet evaluated. In addition to these more typical side effects, individual drugs may also have other specific side effects.
Misconception #4: It takes thousands of dollars to treat my pet for cancer.
Truth: An important responsbility of our team is to develop a list of treatment options that can be financially acceptable to a family. Some forms of cancer therapy for pet animals are expensive. Having said this, there are often alternatives to these conventional options. For instance, clinical trials and compassionate use programs involve novel anti-cancer therapies that may be provided at no cost. In some instances, these programs may also provide support towards the costs of some, if not all, care related to a patient.
Misconception #5: My dog is old, is it worth it?
Truth: Cancer typically affects senior companion animals; therefore, most of the information that we have regarding the efficacy and tolerability of the chemotherapy/radiation therapy protocols already takes into account the use of these treatments in older populations of animals. Concurrent illnesses (i.e. kidney, heart, liver, disease) have to be assessed and considered by our team as we develop and discuss the treatment options of your pet.
Basic Cancer Vocabulary
There are some terms that you should be familiar with to better understand your discussion with your primary care veterinarian and your oncologist. These terms are the most commonly used when discussing cancer.
- Cancer (Synonyms: Malignancy, Neoplasia): Abnormal cells that have gained survival advantages that allow them to divide without control and to invade other parts of the body (metastasis). Cancers can either be a solid tumor (carcinoma, sarcoma) or they can be hematologic (blood bourne), like those seen with lymphoma or leukemia. The most common types of cancers include: carcinomas, sarcomas, round cell tumors, and leukemias. Check out our glossary of pet cancers for more information.
- Diagnosing Cancer: Here are the most common ways that we diagnosis cancer and determine the extent of the disease to decide on the best treatment:
- Information from the tumor: Using either histology (assessing a section of tumor tissue often called a biopsy) or cytology (assessing a sample of tumor cells from a fine needle aspirate), we can obtain an idea of the cell of origin. Histology is the only method where we can determine the tumor grade (predictor of local behavior and mestatic potential) and the completeness of surgical excision (surgical margin evaluation).
- Tumor Stage: The stage of a cancer is an evaluation of the extent of the disease in the body. This is based on the T-tumor, N-node (lymph node), M-metastasis system, and is a reflection of the information obtained from additional testing including bloodwork, urinalysis, chest/abdominal imaging, regional lymph node evaluation, etc.
Types of Cancer Treatment
- Surgery: Surgery is a local therapy often used to either remove the entire mass, to eliminate disease, or to debulk the tumor to microscopic disease in hopes for heightened success with follow-up (or adjuvant) treatment.
- Chemotherapy: Systemic treatment given with the intent to kill rapidly dividing cancer cells in the primary tumor and throughout the body.
- Targeted Therapy: Systemic treatment that is directed at certain aspects of the tumor cells (receptor tyrosine kinase inhibitors), and, because it is more directed, may be associated with fewer side effects than chemotherapy targeted therapy.
- Radiation Therapy: A form of local therapy that uses high-energy radiation to kill cancer cells and shrink primary tumors.
- Palliative/Supportive Care: Therapy that addresses the symptoms and side effects of the disease in order to improve quality of life, but does not address the cancer.
Check out our glossary of cancer treatments for more information.
When to Seek an Oncology Consultation
What is a veterinary oncologist?
A veterinary oncologist is a veterinarian who has undergone additional, specialized training in oncology following veterinary school. Upon successful completion of 2-3 years of training in the field and several examinations, these veterinarians are considered board-certified, and are designated by the title of DACVIM-Medical Oncology. There is also a subset of highly trained veterinarians whose practice focuses on oncology. A good resource is the American College of Veterinary Internal Medicine. There you can search under your state and zip code for area veterinary oncologists.
What can I gain by seeing a veterinary oncologist versus my primary care veterinarian?
During an oncology consultation, your pet will have:
- a thorough history obtained about their disease (onset of clinical signs/tumor, growth rate, previous therapy and response, etc.) and concurrent medical conditions
- a physical examination
- a review of any staging tests performed (bloodwork, urinalysis, radiographs, biopsy/cytology results, etc.)
- a discussion about additional diagnostics needed
After all the information is obtained, the oncologist will then integrate all pertinent findings and provide information about the diagnosis, the treatment options available (including the goals), the side effects, and the costs associated with that therapy, and will then help tailor a customized treatment plan to fit your pet’s and your family’s goals and needs. Treatment for your pet will be followed up either with your oncologist (if pursuing chemotherapy/targeted therapy/radiation therapy), or coordinated with your primary care veterinarian.
We hope that the above information helps lessen the stress and confusion associated with your pet’s recent cancer diagnosis. We are here to help serve you and your pet’s needs and look forward to helping you and your family.