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Mammary Tumors in Cats
Mammary tumors
Mammary tumor
Mammary tumor
also see Cancer in cats
Question: I found out on july 8 that my cat boo, has mammary cancer.he's had a
radical unilateral mascetomy and the biopsy shows that its in his lymph
glands but not in his lungs which was the reason i chose to put him
through the surgery in the first place because they were clear. so far,
I have chosen not to do chemo or radiation etc . I am waiting for my vet
to find out which lymph nodes it was found in and the size of it.
because i want to possibly track the most likely course it will take so
i can prepare for his end days to make him as comfortable as possible. I
am being a realist about this and know how dismal the outlook for boo is
,and to put him through treatment seems selfish .although if my vet said
to me that a certain treatment would give him quality and quanity,
quanity in my head being 2-3 years i'd take the chance because i love
him so and i know he loves living life. they gave him a few months. last
summer he weighed 19 pounds and now he ways 10 pounds although he
does'nt look emmeciated because he is a big cat and his appetite for the
most part is pretty hardy.By the way he's a long haired black brown bear
of a cat and just happens to have a little siamese in him, read its
prevelent in them although its extremly rare in male cats of any
distiction. I quess I'm writing to you for any insight on this matter
,and conformation on my decision that ya miracles happen ,but is it worth
the risk, expense, and disappointment if all fails. looking forward to
hearing from you doc. karenAnswer: Karen-
Mammary tumors occur less commonly in male cats than in female cats, as you
are aware. Prior use of megestrol acetate (Ovaban Rx) in a male cat can
predispose to mammary tumors. I do not know if this would change the
prognosis if it were found to be the problem, but I think a veterinary
oncologist might know.The prognosis for mammary tumors in cats varies the most based on the size
of the tumor when it is removed. For tumors less than 2cm in diameter the
prognosis is best. Cats with tumors of this size at the time of the surgery
have a median survival time post-surgery of about 3 years. For tumors
greater than 3cm in diameter, the median survival time is less than one
year. This is from MacEwen EG et al, "Prognostic factors for feline
mammary tumors" Journal of the American Veterinary Medical Association, 1984.Sometimes the pathologist gives an indication that the tumor type appears
to be especially aggressive and this should be factored into decision
making, as well. As you have done, X-rays of the chest and examination of
any fluid found in the chest to look for metastases prior to doing surgery
is best. Removal of regional lymph nodes at the time of surgery is
generally recommended, as well.The most common recommendation for dealing with mammary tumors in cats at
this time, in the references I have, is to do a radical mastectomy of both
mammary gland chains and to spay females who have not been spayed already.
(I know that doesn't apply to Boo).If the tumor was less than 2cm in diameter I think that surgery alone may
be all that is necessary. For tumors over 3cm in diameter chemotherapy will
benefit approximately 50% of cats and in that circumstance it seems
worthwhile to consider it. The decision is hardest when the tumors are 2 to
3 cm in diameter. In this case, the lymph node examination and
pathologist's opinion may help in decision making.It is best to consult with an oncologist about chemotherapy since
chemotherapeutic profiles change somewhat frequently. At the present time,
I think that combinations using two or more medications among adriamycin,
cyclophosphamide, mitoxantrone and/or carboplatin are the most common
recommendations.If this doesn't cover the questions entirely, please feel free to write for
clarification.Mike Richards, DVM
8/4/2000
Question: My 8 yr. old cat has a mammary tumor and is having surgery next
week. I want as much info on this subject as possible. I have other
pets, too, and keeping up with VET news will keep me "on the cutting edge!"
Elizabeth-
Answer: Mammary tumors in cats are malignant approximately 90% of the time.
This makes it very important to try to remove them as early as possible, so it
is good that you are going ahead with surgery.It is a good idea to have X-rays taken of the chest of cats prior to
surgery for mammary tumors, since some cats already have metastatic tumors
in their chest at the time that the tumors are found. In cats, the tumors
in the chest may look like interstitial pneumonia due to many small tumors,
rather than a large mass that is easily seen.Tumors that are less than 2cm in diameter have a much better prognosis than
tumors that are over 3cm in diameter. In between, the prognosis must be
really variable because it doesn't seem to get reported. For tumors less
than 2cm, the mean life span after surgery is supposed to be about three
years. For tumors over 3cm in diameter the mean survival time is supposed
to be about 6 months.Most surgical texts recommend doing a unilateral mastectomy in cats with
mammary tumors affecting a gland on one side. Cats usually have 4 pairs of
mammary glands and a unilateral mastectomy is removal of all 4 glands on
one side. If there are tumors in the other mammary gland line (sometimes
these are hard to find prior to surgically prepping the patient) it may be
possible to remove the mammary glands on both sides at the same time but
usually it is necessary to remove the most severely affected side and wait
three to four weeks for that side to heal before removing the mammary
glands on the other side. "Lumpectomy" is not a recommended procedure for
cats for most cases of mammary gland cancer. I do think that a case can be
made for removing the lump if there is some reason to question what it is
during the surgery (if it just doesn't look like cancer) and then
submitting it for histopath and going back and removing the whole mammary
line if it does turn out to be an adenocarcinoma but not many veterinary
surgeons agree with that approach, based on the literature.It is a really good idea to have a pathologist examine the tumors after
removal. Each individual tumor found should be examined, if possible. In
cats, lobular hyperplasia and fibroepithelial hyperplasia can be mistaken
for mammary tumors, according to Dr. Fossum's book, "Small Animal
Surgery". The pathologist can also give some idea of the likelihood of
malignancy and the prognosis based on examination of the tissues.At the present time there is not a lot of enthusiasm for chemotherapy as a
primary treatment and not much more for it as an follow up to surgery,
either. However, this information changes rapidly and if the lumps do turn
out to be mammary adenocarcinoma (most common type of mammary tumor in
cats) it would be a good idea to ask your vet to check with the oncologist
he or she refers cases to for the latest information on chemotherapy for
this condition.The last "mammary tumor" we removed from a cat turned out to be a
granuloma ( a benign mass), so there are some times when a good outcome
occurs. I hope that you have this kind of luck.Mike Richards, DVM
4/29/2000
Mammary tumorQuestion: Hello,
I just recently subscribed to this service because I have a question about
my 12 year old Siamese cat.I took her in to the vet about three weeks ago because I found a growth that
appeared near her mammory glad. The vet said that it was probably a mammory
glad tumor and that it was probably bad news. She did testing that day -
blood work and a some sort of sample of the gland or of the growth. When
she called me she told me that it could be good news because it was more
liquidy than tumors and more like a cyst. When the tests came back, she
seemed to think that it was benign. She recommended that I still remove it
though, just in case. We made an appointment two weeks later for surgery.
When I took her in for surgery, they called me after they did the x-ray.
They said that it actually did look like cancer and it looked like it had
spread to her lungs. They said that there was really nothing that they
could do. They said that surgery would not help the cancer go away, but it
might alleviate pain related to possible ulceration that could occur later
to the tumor. Because the tumor is not ulcerated now and they said that
there were also great risks of going into surgery when cancer had progressed
that far, I decided not to have it removed.What I want to know, if you can help, is did I make the right decision?
And, most importantly, is there really not anything that can be done now?
Also, did waiting two weeks to go into surgery cause it to spread to the
lungs? Please help me if you can - I love my cat so much and I don't know
how to deal with this. What can I expect and how can I make it easier for
my kitty. She does not seem to know what is going on now, but I assume that
she will soon?Thank you very much, C. M.
Answer: C-
I think it would be a good idea to ask that the X-rays be evaluated by a
veterinary radiology specialist. While there are many veterinarians who are
quite skilled at reading X-rays, general practitioners just don't see as
many X-rays as specialists. Getting a second opinion on an X-ray of this
importance is warranted.Surgical excision of mammary tumors is recommended if they have not spread.
Radical surgical excision is usually best in cats due to the high rate of
malignancy of mammary tumors in cats. Chemotherapy is helpful in some cats,
usually using adriamycin, but it does not appear to help in all cases. If
the tumors have spread to the lungs, the prognosis is very bad. If you wish
to try to treat, anyway, then chemotherapy is probably the way to go. There
are veterinary oncology specialists and it is worthwhile to have one
consult with your vet, or possibly see your cat, to give you the best
evaluation of the possibilities for therapy.This is a very tough situation to be in. It is not likely that the delay of
two weeks made a significant difference. There are no statistics that I
know of to evaluate the risks of waiting between initial clinical signs and
treatment, in cats, but for similarly aggressive tumors in humans a wait of
this time period doesn't seem to affect the outcome much.I am sorry that I can't be much more help. I really do think it would be
best to have the X-rays looked at. They can be sent by overnight delivery
to a radiologist and you can have a second opinion pretty quickly.As time goes on, concerns such as appetite maintenance, pain relief,
complications of chemotherapy or other things related to this problem may
come up. Please feel free to write and ask questions about any of these
matters.Mike Richards, DVM
12/16/99
Last edited 01/30/05
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