Good Outcome After Canine Mammary Cancer Surgery
This is Cinnamon. Isn’t she adorable?
Notice the grey hair? Notice a little cloudiness in her eyes? Cinnamon is no youngster. Indeed, despite her small size, she’s almost 11.
For whatever reasons, Cinnamon didn’t have spay surgery when she was young. Previously we have discussed how that predisposes dogs to mammary (breast) cancer. Now, time has caught up with Cinnamon and she has a large, firm, suspicious lump that we must deal with. Fifty percent, half, of canine mammary growths are malignant.
So, here’s the approach:
Surgery in two parts: First we will remove the uterus and both ovaries (ovariohysterectomy) or spay surgery. Second, we will remove the actual mass. Why remove the reproductive organs first? Leaving Cinnamon “intact” or unspayed is not an option, as hormones from the ovaries would continue to stimulate the mammary glands to produce more abnormal cells, at least half of which may be cancerous. By performing all of these steps first we minimize the risk of “seeding” other tissues of the body with abnormal cells from the tumor. Such transplantation is actually easy and cancer cells so-moved will grow readily in the new sites.
The next step is to submit the mass to a board-certified veterinary pathologist for histopathology. He will section it (make thin slices), stain it and look at it under a microscope to determine its characteristics, especially whether it is benign or malignant.
Notice the size of Cinnamon’s uterus (below, right). A normal uterine size for a dog this age, while larger than a 4-month-old puppy’s, should not be this big. Now observe that when the uterine wall is incised (directly below) and its interior exposed that there is a dark discharge and irregular, bubbly surface. Infection and fluid in the uterus make the ovaries “think” the uterus is pregnant, causing production of hormones of pregnancy and enlarging the uterus further. Simultaneously, milk glands are stimulated, which can aggravate a tendency to form even more abnormal mammary cells.
By comparison, look at “Octomom’s” uterus (below, left). Cinnamon weighs 6 1/4 pounds and Maggie weighs 42 pounds. Their uteri are almost the same size. Considering that Maggie is only two months postpartum delivering eight puppies, you quickly understand that Cinnamon’s uterus is dramatically enlarged.
Great news came in today! Just six days after Cinnamon’s surgery we got the report that her abnormal tissues were completely benign and completely excised. Therefore, we should have no recurrence of this tumor.
The question arises, “What if tumors were already growing prior to the surgery?”
There are two answers.
Benign preexisting growths, lacking the “fuel” of ovarian hormones are unlikely to progress.
The behavior of malignant growths, however, is less predictable. I spoke to Dr. Elizabeth Kergosien, D.V.M,
DACVIM (Oncology), who shared the very latest information on this topic. “In cases where known malignant mammary masses are present, removal of the uterus and ovaries makes no difference” she says.
The bottom line? Avoid mammary cancer and unwanted pregnancies by having puppies spayed before the first heat cycle. The risk of mammary cancer in these pets is very close to zero.