Introduction
A feline problem that we encounter in predominantly
outdoor, white haired cats is a cancer called Squamous Cell Carcinoma (SCC).
Excessive amounts of sunshine are the main source of the problem, so the disease
is prevalent here in California. White haired cats have more than a 13 times
greater risk of getting this disease than do cats of other colors, due to their
lack of pigmentation.
At the end of the surgery pictures (don't worry,
they're not bad) is a short video on using the laser to correct this problem.
The laser is our preferred method of treatment. You need Quicktime from www.apple.com
to get it to play.
Symptoms
White haired cats usually get the
problem on the ears, head, eyelids and tip of the nose. Cats that are
not white usually develop the lesions on unpigmented areas or areas
of sparse hair. It occurs mostly in older cats, but the age at which
it occurs depends on each individuals' amount of exposure to sunshine
and lack of pigmentation .
Early symptoms of the disease can
be subtle, such as a minor irritation or scab on the head, ears, or
nose. In more involved cases there is obvious redness, irritation,
scabs, and hair loss. These symptoms mimic other diseases, especially
skin conditions caused by Ringworm,
Sarcoptic
mange and allergies,
so an accurate
diagnosis is
imperative.
This tiny ulceration at the tip of this cat's nose is
typical of the subtle lesion that is possible with
SCC.
The small red spot on this cat's ear could also be
caused from SCC.
Diagnosis
It is important to make a correct diagnosis early in the course of the disease because
it can significantly affect the final outcome. The primary method of diagnosis
for this disease is a skin biopsy. Any suspicious lesion should be biopsied
since the prognosis is much more favorable the earlier the treatment. Many
cats have lesions that are so suggestive of the disease that we perform surgery
at the same time.
Most SCC's do not spread throughout the body,
but they can recur at the site of the original lesion. Those that do spread
will go to lymph
nodes and the lungs. Prior to any
treatment it is important to take a blood sample, a chest x-ray, and a sample
of lymph node tissue for analysis. This helps stage the disease and let us know
what the proper treatment regimen should be. All cats with this disease must
be tested for FeLV
and FIV
This
is the radiograph of a dog that has cancer that has spread
to its chest. The arrows point to small white areas that are
the actual tumor masses that are in the thorax. They lodged
here after spreading via the bloodstream from the original
tumor located elsewhere in the body.
Treatment
Squamous Cell Carcinoma is a
malignant cancer that needs immediate and aggressive therapy if we
hope to arrest it. The primary treatment
method is surgical. It involves removal of the affected area or
partial amputation of the ear or ears.
If the lesion is on the nose or head a great effort is made
to preserve a cosmetic look. Again, this emphasizes the need for an early diagnosis.
If the lesion is on the ear then a partial amputation of the ear is performed.
It is important to remove a significant amount of the ear because recurrence
is common if the amputation is incomplete. The redeeming part of this surgery
is the fact that most cats look great when healing is complete.
Some
SCC lesions are very extensive. In a case like ashley's,
we have to amputate almost the whole external ear due to
the extensive nature of the lesion. We prefer to care for
these situations long before they become this
extensive.
This
cat has been positively diagnosed with SCC on both of its
ears, even though the problem only seems minor compared
to ashley. The small amount of redness and the minor
scabs are the only apparent lesions. It is under general
anesthesia,
has been prepped for surgery and the amputation of both
ears is about to begin.
The following pictures are
from an actual partial ear amputation that we performed at our
hospital. If you do not want to view them click
here
to see the ears when they are healed and to continue learning
about SCC without looking at the actual
surgery.
Since
it is impossible to determine just how far the tumor has
spread, wide margins are cut to minimize the potential
for recurrence.
The
delicate suturing of the ear takes the most time in this
procedure. The cosmetic appearance when healing is
complete makes the time invested well worth it. Before
your pet wakes up from anesthesia we will give it
pain
medication to
minimize discomfort.
This
is the appearance of the ears immediately after surgery.
The look longer than they actually are because the hair
around them has been clipped extensively. Within 7-10
days these sutures will be removed.
Four
weeks later this is the final appearance. Many people do
not even notice that any surgery has been performed. It
is important to keep this pet out of the sunshine
indefinitely.
We routinely perform this surgery using the
carbon dioxide
laser. The significant advantages are
minimal bleeding during the surgery, negligible post operative pain,
and no need to put sutures in for some cases. This short QuickTime
movie below shows the initial incision with the laser, and just prior
to suturing- note the lack of blood. Make sure you have QuickTime
from apple.com on your machine and double click the box below.
SSC can occur in other locations.
It is one of the most common causes of cancer of the mouth of older cats (not
in dogs). It can occur in the lower jaw, upper jaw, or tongue. Typical symptoms
might include halitosis, difficulty eating (dysphagia), and drooling, although
being the mysterious creatures they can be, the SCC can be present without any
outward signs. This is a big problem regarding treatment, since we usually diagnose
these cases after the disease is well entrenched and our ability to correct
the problem is minimal. At this stage of the disease these cats might only live
several months after diagnosis. Older cats need frequent exams to catch this
disease and other geriatric
diseases before they have progressed
too far.
This
cat has it on its lower jaw (arrow) on the right side.
The diagnosis was verified during a biopsy while its
teeth
were cleaned.
SCC can mimic tooth root abscesses, so biopsies are
recommended if we suspect it while cleaning your cat's
teeth.
A closeup view shows how extensive the
problem is. The only treatment at this point is to remove this side
of the whole lower jaw. If the problem is in the tongue chemotherapy
can be used to prolong life. Radiation therapy can be used if the problem
is in the upper jaw. We recommend a feeding
tube in these cats to aid
in their nutrition.
The
radiograph of this cat shows how extensive the lesion is.
There are two areas to note on this view of the lower jaw.
The right jaw bone is affected. It has a moth eaten
appearance that can be visualized by comparing it to the
left side of the jaw. In addition to the bone lesion, the
tissue of the mouth surrounding the bone is also affected.
This is visualized on the radiograph as the whitish area
surrounding the right jaw bone. This is the tissue that was
biopsied to confirm the diagnosis. at this stage of the
disease the jaw on the affected side needs to be completely
removed. This surgery will be undertaken only if there is no
evidence that the tumor has spread by taking an x-ray of the
chest and biopsying one of the lymph nodes in the neck. It
is an extensive surgery, yet most cats do fine
postoperatively.
This dog has SCC at its toe (arrow). You can see
how the bone is being destroyed.
We
amputated the toe all the way up to the metacarpal joint.
The arrow points out where the toe used to be. This
radiograph looks different from the one above because it
was take immediately after surgery and there was a
bandage on the foot.
Additional Treatment
Regimens
A new and promising treatment for SCC is called
Photo Dynamic Therapy. It involves the use of a laser beam to selectively destroy
cancerous tissue only. An injection of photosensitive chemical is given to a
pet that has SCC. The only cells that absorb this chemical are the cancerous
ones. It is only these cells that are destroyed by the laser, the laser beam
harmlessly passes through the normal cells that do not absorb the photosensitive
chemical. If one of our doctors feels that this therapy is appropriate, they
will let you know. It is considered experimental therapy, and is performed locally
only at the Beckman Laser Institute at the University of California at Irvine,
on a referral basis only.
The best method of prevention for
skin SCC is to eliminate exposure to sunshine. The use of sun block
on the tip of the nose and ears is helpful if your cat does not lick
or rub it off. White haired cats should be kept indoors, and should
be prevented from sunbathing for long periods of time in the window.
Even though windows filter out ultraviolet radiation, they do not
filter enough of the radiation in the case of SCC.
Older cats need exams at least
every 6 months to aid in the early diagnosis of the other forms of
SCC
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