-----Cancer in Animals
River Road Veterinary Clinic
Box 309
Norwich, Vermont 05055
Phone: 802-649-3877 Fax: 802-649-1345
email: RRVC@Valley.net.com
www.rrvetclinic.com
Dr. Christine Pinello - Dr. JoAnne Giel - Dr. Kathy Ling Newcomb
Cancer in Companion Animals
Article written by: New England Veterinary Oncology Group, LLP
Terminology
Your pert has been diagnosed with cancer. Cancer is a disease that is
due to the uncontrolled and purposeless growth of cells in the body.
The terms cancer, malignancy, and neoplasia are synonyms. Cancer is
not a single disease since it can arise from any tissue in the body.
Therefore, there are many types of cancer. Some forms of cancer have
the ability to spread to other sites in the body that are often far
from the original site. This occurs when cancer cells enter the blood
or lymph vessels and are carried to other organs. Cancers with this
type of behavior are considered malignant. Oftentimes, it is the spread
of a cancer that causes the greatest problems. When a cancer has spread
in this fashion, it is said to metastasize. Some cancers lack the ability
to metastasize but may cause significant damage due to growth and invasion
into local tissues. Tumors that do not metastasize and are not invasive
are considered benign. The term, tumor, is a general word for cancer
whether benign ("good" cancer) or malignant ("bad"
cancer). Oncology is the branch of medicine dedicated to the study of
cancer and the veterinarians treating your pet at NEVOG are oncologists.
Tumor Evaluation (work-up): Tumor Staging
The first task of your veterinarian is to determine the extent of the
tumor. This information is vital for several reasons including determination
of your pet's prognosis (i.e., the expected outcome for your pet as
a result of the cancer) and formulation of a plan for treatment.
To gather information that can help determine the extent of the cancer,
your clinician will need to evaluate your pet by several methods. These
usually include blood tests (e.g., blood count, chemistry profile),
urinalysis, radiographs (x-rays), tissue aspirate, and biopsy. Tests,
which you local veterinarian may have performed, might be repeated at
NEVOG due to the changing nature of your pet's illness. In addition,
as indicated for specific patients, other testing procedures may include,
ultrasound, specialized radiologic studies (e.g. nuclear scan, CT/MRI
scan, contrast studies), bone marrow aspirate, lymph node aspirate,
endoscopy (direct examination of the stomach, colon, or bronchi with
a specialized scope), and immunologic studies. The collective process
of obtaining this information to ascertain extent of the cancer is referred
to as tumor staging. It is important to realize that medicine is not
an exact science and that despite these staging procedures, small sites
of tumor or tumor in organs that are difficult to study may not be detected.
Once the tumor staging has been completed, we will be better able to
discuss treatment options for your pet. The goal of such therapy will
also be discussed. Tumors that have metastasized extensively are usually
not curable. Therefore, the objective of therapy for these animals is
palliation (i.e., afford relief of symptoms and possibly prolong life
without providing a cure). Localized tumors that are not deeply invasive
have the best chance to be cured.
Cancer Therapy
There are several types of therapy used to treat cancer in dogs and
cats at NEVOG. These include surgery, chemotherapy, and radiation therapy.
For some tumors, treatment will consist of a single type of therapy,
while combination therapy may be recommended for other types of cancer
or for animals with more advanced stage of disease. On occasion, due
to the rarity or biological behavior of a particular tumor, a precise
treatment recommendation may not be known. In an effort to test newer
(and hopefully more effective) forms of therapy, you may be asked to
enroll your pet in an investigative clinical trial. The purpose of such
a trial is to learn more about the specific type of treatment (that
may be of value to humans and other pets with cancer) as well as hopefully
providing a benefit to your pet. Only pet owners of animals with tumors
for which there is no effective investigative therapy for their pets,
if appropriate investigative treatment is available.
Should you treat your pet?
Treating animals with cancer is not appropriate for every pet or family.
It takes a strong commitment on the part of the owner. Therapy requires
frequent trips to the veterinary hospital and can be expensive. For
some forms of cancer, treatment, once begun, is never stopped during
the animal's life (although frequency of treatments can be decreased).
Your veterinarian cannot do it alone since treating pets with cancer
is truly a team effort and the pet owner is on the team. It is important
for you to present your pet for treatment precisely when requested to
do so by your veterinarian since the timing of cancer therapy is critical
for obtaining an optimal outcome. In addition, medicines to be given
to your pet at home should be administered by you exactly as requested
by your oncologist. Any abnormalities or problems you encounter should
be reported to your local veterinarian or oncologist promptly. Always
feel free to ask questions and communicate with your veterinarian.
Keep in mind that your veterinarian is as concerned about the quality
of your pet's life as you are. The goal of therapy is to keep your pet
happy and minimize discomfort. Although some animals may experience
transient discomfort form therapy, treatment of most pets with cancer
can be accomplished without major distress or detraction from your pet's
enjoyment of life. Just because an animal has been diagnosed with cancer
does not mean its life is immediately over. Your commitment to your
pet and your veterinarians' dedication to providing state-of-the-art
care will work together to keep your pet as happy as possible.