Terminology
Your pet 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 which are
often far from the original site. This occurs when cancer cells enter
the blood or lymph vessels and are then 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 is is 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 VHUP 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 to determine the extent of
the cancer, your VHUP 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 your local veterinarian may have
performed might be repeated at VHUP 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, dye 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, your veterinarian
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 the University of Pennsylvania. These include
surgery, chemotherapy, radiation therapy, and immunotherapy. 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 treatment or tumors that
have not responded to conventional treatment will be offered
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 the 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 us.
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 from 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 it's 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.