Canine Mammary Gland Surgery
Mammary gland tumors are
common in the dog, and surgery to remove cancerous mammary glands, called
a mastectomy, is a
routinely done procedure in veterinary medicine. Male
dogs almost never get mammary tumors; as well, female dogs that have
been spayed before their first heat cycle rarely acquire breast cancer.
Statistics demonstrate that if a female dog is spayed after her first heat
cycle but before her second cycle, her potential to develop mammary tumors
is slightly greater than the dog that was spayed prior to a heat cycle.
If two cycles occur, then the spay procedure, an even higher incidence
of breast cancer is demonstrated. And spaying after three heat cycles
has no effect on diminishing the potential to develop mammary tumors.
In short, the sooner a dog is spayed the less the chances for mammary tumors
to develop in the future; but after three or four heat cycles, spaying
has almost no effect on protection against tumor development. Keep
in mind that spaying any dog at any time (as long as the patient is healthy)
may be advisable to prevent a very serious uterine infection called PYOMETRA. Also see images of the SPAY (technically called an Ovariohysterectomy) surgery
Bitches are prone
to mammary tumours, most of which are benign, meaning they will not spread.
However, up to half of cases can spread to the lungs and other organs.
Male dogs also get mammary tumours, but these are uncommon and tend
to be benign. As in humans, treatment options include surgery, radiation
therapy or chemotherapy, though very few vets can offer all these options.
Bitches that are
spayed after their second season are 50 times more likely to get mammary
cancer than those spayed before their first season. Obesity also increases
risk, especially if dogs are obese at one year old.
If you feel a lump
in your dog's mammary gland, I recommend you ask your vet to take a look.
Many bitches have more than one type of tumour present, but most lumps
will cause no further problems once they have been removed.
Breast Cancer Surgery (Mastectomy) In The Dog
Visual inspection and a physical exam probably will not be helpful
in determining whether or not a growth is benign or malignant. A biopsy
can be done on these growths to determine the cell types, which are highly
variable in canine mammary tumors, and to establish the degree of malignancy.
Malignancy means that they have the tendency to spread invasively into
surrounding tissues and also to be spread by the lymph system to other
parts of the body. Most veterinarians will suggest a chest
X-ray prior to any mammary gland surgery to see if there is any evidence
of metastasis (new tumors as a result of "seeding" from a distant, primary
tumor). If there is evidence of tumor spread to other areas, the decision
to do a mastectomy may not be advisable because metastasis of mammary gland
tumor to the lungs or other body tissues almost always signals a very poor
prognosis for recovery in the dog.
Chemotherapy for mammary gland cancer, and/or radiation treatment,
can be done but the main effort of treatment is surgical excision of any
The case shown below is of an eight year old dog that had been spayed
and that had small masses in the right third, fourth and fifth mammary
glands for a number of months. All of a sudden a rapidly growing
tumor near the right fourth nipple attracted the owner's attention and
surgery was performed. There was no evidence of metastasis in this
patient and removal of the third, fourth and fifth mammary glands was done.
Since there was no evidence of tumors in the first and second gland, those
were left intact but careful vigilance will be needed to ensure that if
any evidence of tumors show up, further surgery may need to be done.
|Mammary Gland Surgery In The
|This view is of the patient
just prior to preoperative preparation of the surgical area for surgery.
The large mass between the fourth and fifth nipple is evident.
|The surgeon, employing
sterile technique, begins the incision near the masses in the glands,
being careful not to incise any tumor tissue.
bleeding) can be challenging in these surgeries due to the mass of tissue
to be removed as well as the vigorous blood supply to the area.
|One side of the three mammary glands
is dissected down to the abdominal wall; then the opposite side is dissected.
|Care is employed to remove all the mammary
gland tissue but also to leave enough normal tissue that closing the incision
will not create excessive tension along the surgical closure.
|Blood vessels are tied off and the row
of three mammary glands is lifted away from the patient. Some veterinarians
will remove all five glands even if no evidence of tumor in other glands
|A major artery and vein to and from
the area is the Caudal Superficial Epigastric vessels. Lymph channels
drain from the last three mammary glands through this small channel through
the abdominal wall.
|After removal of the mammary glands
(along with the tumor tissue) the incision is closed in layers from deep
to superficial. The goal is to comfortably close the incision with
no tension being placed on the skin.
|In this case the skin is closed via
two simple continuous sutures to decrease surgical and anesthetic time.
The patient is placed on pain control medication for a few days and sutures
are removed in 12 days.
It is a good idea to routinely
(about once a month) check your dog for breast tumors. If anything
unusual seems to be present, than have your veterinarian do a thorough
physical exam. At this time a discussion regarding the pros and
cons of surgery is important. Remember, it is always easier on the
patient to have a small mass removed as contrasted with the removal of
a large amount of tissue such as in this case.
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The above information is simply informational. It's intent is
not to replace the advice of a veterinarian nor to assist you in making
a diagnosis of your pet. Please consult with your own veterinarian for
confirmation of any diagnosis. Your pets life may depend on it.