healthwatch
So Your Dog Has Cancer, Part I
BY KEVIN T. FITZGERALD, DVM, DABVP
Because canine cancer is common, it is important
to familiarize yourself with the disease.
ANCER IS A DISEASE that every-
one seems to be aware of. Most
people have had a friend or family
member who has developed some form
of the disease. Presently, it is estimated
that one out of every four people alive
will eventually display some form of
cancer. Dogs, like people, can contract
a number of types of cancer. Due to
inbreeding and the maintenance of
purebred lines, dogs have a 33 percent
greater overall incidence of tumors than
humans do. Tumors (clusters of cancer
cells in the body) can occur in any part
of the body. The incidence of particular
tumors varies not only among species
(dogs versus cats versus people), but
between sexes — and in dogs, among
breeds.
The purpose of part one of this article
is to familiarize you with basic cancer
vocabulary and discuss the incidence of
cancer in canines. Part two (in the
C
November/December issue)
will discuss specific tumors
seen in working dogs in law
enforcement, how to recognize those tumors, and what
can be done to treat them.
Cancer has its own language.
The study of cancer is
known as oncology. Someone
who is a specialist in treating
cancer is an oncologist. A
benign tumor retains a
recognizable tissue of origin.
Typically, benign tumors
are localized and well
encapsulated. Benign tumors
show no signs of metastasizing. Metastasis is the spread
of tumor cells via blood or
lymph or along tissue planes
to distant sites in the body
(heart, lungs,
brain), where they
wedge, establish a
blood supply, and start to
grow. Malignant tumors lose
recognizable tissue of origin
(their cells become bizarre)
and are not well encapsulated or localized. They are
diffuse, invasive, and it is
difficult to tell where healthy
tissue begins and the tumor
stops.
PHOTOGRAPH: COURTESY OF ACEK9.COM
The most important
characteristic of malignant
cells, however, is their ability
to metastasize. That disturb-
ing capability means that
sometimes when a tumor is
discovered, often it has
already spread throughout
the body.
