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Introduction
A feline problem that we encounter in
predominantly outdoor, white haired cats is a
cancer called Squamous Cell Carcinoma (SCC).
This is a serious disease, but if caught early
there is so much more we can do about it.
Vigilance on your part is the key to noticing
any abnormalities warranting an exam by one of
our doctors.
The skin version of SCC is caused by excessive
amounts of sunshine, 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.
The oral version of SCC is particularly
aggressive as opposed to the skin version of
SCC in white haired cats. 90% of cats with
oral SCC are dead within 12 months of
diagnosis.
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.
Oral Tumor Behavior
This is a particularly aggressive form of the
disease that has unique biological behavior.
The oral version of SCC can occur anywhere in
the mouth or jaw, and only occasionally
spreads. Under the tongue, called the
sublingual area, is where it is found most
often.
Many other tumors tend to be found in the
lungs when they spread. This is not the case
for oral SCC. If it spreads it is oftentimes
found in the submandibular lymph on
the same side of the mouth as the tumor.
These tumors grow rapidly and are usually well
entrenched by the time a diagnosis is made. At
this stage the prognosis is poor, so early
detection is vital. This as another
affirmation of the need for complete physical
exams in cats, especially as they age. Older
cats need frequent exams to catch this disease
and other geriatric diseases before
they have progressed too far.
The average age of cat with oral SCC is 12
years, although it has been diagnosed in cats
much younger. It can occur in most any breed
of cat. One year survival rate is less than
10%.
Typical symptoms might include halitosis,
difficulty eating (dysphagia), and drooling,
although being the mysterious creatures they
can be, the oral SCC can be present without
any outward signs.
Is postulated that cats exposed to tobacco
smoke have an increased chance of getting oral
SCC. This is the same for cats wearing flea
collars and those that ate canned food as
opposed to dry food, especially canned tuna.
It is not sure why cats eating dry food has
less SCC, possibly because they might have
less tartar leading to better oral hygiene.
More work needs to be done in these areas to
delineate a cause.
The oral cavity is a common site for SCC,
accounting for 10% of all feline tumors.
This cat has the tumor under its
tongue. At this stage of the disease these
cats might only live several months after
diagnosis.
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. This is called a
mandibulectomy. 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. Neither
treatmen is rewarding. 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.
If we do not remove the jaw on this side
the problem will not be solved.
Symptoms
In the skin version of SCC 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.
Diseases that can mimic the oral SCC include:
Tumors
Fibrosarcomas
Lymphomas
Melanomas
Adenocarcinomas
Mast Cell Tumors
Infections
Cryptococcosis
Blastomycosis
Actinomycosis
Dental Lesions
Periodontal
disease
Endodontic disease
Benign growths
Polyps
Epulis
Gingival hyperplasia
Eosinophilic granuloma
The primary method of diagnosis for this
disease is a skin or mouth biopsy. Any
suspicious lesion should be biopsied since the
prognosis is much more favorable the earlier
the treatment. If we suspect oral SCC we might
peform a biopsy or Fine Needle Aspirate (FNA)
of a nearby lymph node. Many cats have lesions
that are so suggestive of the disease, or the
tumor is so large, that we perform surgery to
completely remove the tumor at the same time
we are doing a biopsy.
Lymph nodes affected with SCC can be normal in
size, as opposed to lymph nodes with other
cancers, especially lymphosarcoma, that can
become substantially enlarged. On another
note, an enlarged lymph node in a cat that has
oral SCC can be negative for the tumor in the
lymph node, and is enlarged for some other
reason. The bottom line- a physical exam only
checking the external lymph nodes by palpation
is not adequate to determine spread of the
oral SCC. An FNA or biopsy of the lymph node
is needed.
Prior to any biopsy we need a blood panel,
urine sample, and Felv/FIV tests. Some cats
with bone lesions due to SCC will have a high
calcium level (hypercalcemia).
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
Cats with SCC, especially the oral version,
are in pain and can be in poor nutritional
state. We determine this with a routine blood
panel examination. Before any surgery we
institute pain control and supplemental
feeding, including a feeding tube if
necessary.
Skin 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 for the skin and oral
versions. It involves removal of the affected
area or
partial amputation of the ear or ears.
Treatment with chemotherapy or radiation are
unrewarding.
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.
When we remvove the jaw (mandibulectomy) on
the affected sid of oral SCC there is the
potential for postoperative complications.
These include excess salivating, inability to
drink or chew (masticate) properly, and
difficulty grooming. This surgery tends to be
more successful when the tumor is small and
located towards the front of the jaw.
SSC can occur in other locations and in other
species besides cats
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 potential 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, especially the oral form.
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