If your cat or dog has a symptom that might suggest the presence of cancer, the veterinarian must first find out whether it is
indeed due to cancer or to some other medical cause. The diagnosis of cancer is not always simple and may require
extensive 'detective' work using a variety of tests. Physical examination may be useful in detecting the presence of tumors
that are easily visible (e.g. on the pet's skin or in the mouth) or that are detectable by touch (e.g. masses in the abdomen).
For most cancers, however, this type of examination is not sufficient and more tests are required in order to reach a
definitive diagnosis and to evaluate how advanced the cancer is. Depending on the suspected type of tumor, these tests will
usually involve a combination of physical exam, blood and urine tests,
cytology or biopsy to confirm the diagnosis of cancer,
imaging studies to evaluate the extent of the tumor.

Blood and Urine Tests
Blood tests can sometimes detect elevated levels of enzymes that may be indicative of a possible tumor. Urine analysis may
find blood or other molecules that may suggest possible presence of cancer in organs directly in contact with urine such as
the bladder. It is generally recommended that middle-aged and older pets undergo urinalysis and blood testing at least once
a year as part of preventive medical care to increase the likelihood of detecting cancer at its earliest and most curable
stage. While blood and urine tests can be valuable diagnostic tools, abnormal lab results are not a sure sign of cancer and
veterinarians cannot rely on lab tests alone to diagnose cancer.

Biopsy is the gold standard of cancer diagnosis in both humans and pets and should be done prior to initiating any type of
treatment whenever possible. A biopsy refers to a procedure that involves removal of cells or a piece of suspicious tissue
for a detailed analysis by a specialist called veterinary pathologist. It is the most common and most certain way to determine
whether the suspected mass is cancer or not. For more information how biopsy is done, please visit the
Biopsy Section.

Cytology refers to the relatively fast and inexpensive examination of individual cells under the microscope to evaluate
whether they appear cancerous. The cells are commonly collected from sources such as skin masses, body cavity fluids,
ear fluid, lymph nodes, urine or blood. Compared to tissue biopsy, cytology has a few advantages such as the cells are
easier to get, causes less discomfort to the pet, is less likely to result in serious complications, and costs less. The
disadvantage of this approach compared to biopsy is that sometimes it does not give accurate or definitive results. For more
information about cytology in cats and dogs, please visit the
Cytology Section.  

Diagnostic imaging refers to multiple techniques that are used to create images of particular parts of the pet's body to aid
the process of diagnosing and evaluating the extent of cancer so that appropriate treatment plan can be selected for the
pet. To learn about several new techniques that are now available for cats and dogs (e.g. CT/PET scans and other
advanced nuclear imaging methods), please visit the
Imaging Section.
© 2007 Pet Cancer Center. ALL RIGHTS RESERVED.
Last updated 2/19/2017
Comprehensive guide to cancer diagnosis and treatment in cats and dogs
Cancer Diagnosis in Cats and Dogs