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Lung Cancers in Dogs
Lung Cancer
also see Cancer in dogs
also see Hemangiosarcoma, Hemangiopericytomas and Hemangiomas
also see Cough
Please note: The most recent medical information is at the top of the page to least current at the bottom.
Lung cancerQuestion: Dear Dr. Mike,
My twelve year old shepherd mix female, BeniHana, was diagnosed last week
with a malignant tumor on her left lung about 4" by 5". It was aspirated
to confirm its malignancy but we do not know what type of cancer it
is. My feeling is that it wouldn't be sensible to attempt to treat it
with surgery, chemo, and/or radiation. My vet didn't want to sway me one
way or the other, however, and I wondered what you thought. Surgery
sounds highly invasive and painful and likely not very practical.
My vet did say we could give her prednisilone (reduce inflammation) and
lasix (fluid reduction), however, as a palliative approach.
My questions are these:
1. What range of time has she got left (without any interventive treatment)?
2. She only coughs occasionally (it started about six weeks ago)--what
other symptoms should I look for to determine how she is faring?
3. Last night, as she slept I noticed fast breathing and her heart, which
has been shoved over by the tumor, was visibly beating against her chest
cavity. I measured its rate to be about 126/minute. Is this anywhere
normal for a 48 lb. dog? If not, what causes the very rapid rate?
4. I am very concerned about her comfort level, and I want to do the
right thing. This is very hard emotionally for me, and probably
physically for her. She still eats well and drinks large quantities of
water. When is the time right to consider euthanasia? I really don't
want her to to have endure much suffering. She already has endured years
of painful hip dysplasia.
5. How common is lung cancer in dogs? Without knowing what type of cancer
it is, can I know whether it can readily metastisize?Thank you so much.
Wendy
Answer: Wendy-
I am sorry, but it isn't possible to tell you much about the expected
behavior of a tumor without knowing what type of tumor it is. Sometimes
the only way to really identify a tumor is to remove it, or to at least
obtain a piece of it surgically, so that a pathologist can examine the
architecture of the tumor for clues as to what it is. This happens most
frequently when cell types have lost most of their identifying features,
making a needle biopsy sample inconclusive. That is a bad sign, usually
indicating a higher tendency towards malignancy and rapid growth, but
beyond that it is isn't possible to say much.Coughing can be evaluated by frequency, harshness and productivity (what
comes up during the coughing episode). Very frequent coughing, deep harsh
coughing and the production of excessive amounts of phlegm, or other
substances such as blood, are signs that a lung problem is worsening.
Tiring readily, weight loss and unexplained fever occur with malignant
tumors when they begin to really use a lot of the body's energy. Anemia is
a frequent problem when malignant tumors are present and monitoring for it
can be helpful in determining if the tumor is causing more problems than
are visible. This is particularly true of tumors such as hemangiosarcoma,
which can cause internal bleeding.126 beats per minute could be within the normal range for a sleeping dog of
her size, depending on what part of the sleep cycle she is in. Dogs have
REM (rapid eye movement) sleep, which is when dreaming occurs in people,
and heart rates can get high during this phase of sleep. The normal heart
rate for dogs that are awake ranges from 70 to 180 bpm, with small dogs
having higher heart rates and larger dogs slower rates, so this heart rate
is not out of the normal expected range when awake. I couldn't find
specific expected heart rate ranges for sleeping dogs.I think it is a really good idea to consider pain relief medications, even
if you are not currently seeing signs of pain. Carprofen (Rimadyl Rx) and
etodolac (Etogesic Rx) are good initial choices. If there are signs of
visible pain it may be better to use narcotic pain relievers such as
morphine or fentanyl (available as Duragesic Patches Rx). It is reasonable
to presume that some pain is present when there are malignant tumors and
these would help with the arthritis, anyway.Most dogs that are reaching the point where they are no longer able to
enjoy life much stop eating, or have drastic reductions in appetite. They
may refuse to play or to interact with their friends. In extreme cases,
they may be totally inattentive to urinary habits or bowel movements,
losing all pretense of normal household behaviors or not even moving away
from a urine puddle or bowel movement. Almost all pet owners have enough
empathy with their pets to recognize the time when their pet has given up
fighting an illness. There is just a time when you stop wondering if the
time is right to consider euthanasia and you just know that the time has
arrived.Primary lung cancer (cancer coming from lung tissue) is rare in dogs, so
the odds are very high that a tumor seen in the lungs is a metastasis from
a tumor somewhere else. This is not always the case but it is a reasonable
presumption. So in most cases, just seeing a tumor in the lungs is reason
to suspect metastatic cancer.It may be worth asking your vet for a referral to a veterinary oncologist
(cancer specialist) or internal medicine specialist, just to hear what the
options are for identifying the tumor and treatment. You may decide that it
isn't something you wish to pursue but you would have a better idea of what
the potential for treatment and the prognosis would be. Sometimes knowing
those things is worth making a trip to a specialist. On the other hand, if
you are certain that you do not wish to pursue surgery, chemotherapy or
radiation therapy then knowing the exact type of tumor and the prognosis is
not quite as important. In that case, just treating the symptoms as they
come along and providing good nursing care until BeniHana lets you know she
is too uncomfortable to be happy may be the best option. Your vet can help
with the palliative measures you mentioned and with pain control.Trying to keep things interesting and giving in the temptation to spoil
BeniHana some with special foods or activities can make her life much more
enjoyable, despite the physical problems that might develop due to the tumor.Mike Richards, DVM
11/4/2000
Last edited 01/30/05
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