How Do You Know If a Cat has Breast Cancer?

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Tinkerbell waits for surgery to try and cure her cancer

What is This Lump on My Cat’s Belly?

Tinkerbell needed help. The 14-year-old long-haired calico cat looked at Doc Truli with calm eyes. She even purred in the examination room! Tinkerbell had a tumor growth on her belly. It felt bad. Knobbly, bumpy, fluid-filled pockets of firm roundness in a 6 cm area in the middle of her right mammary chain. Not good. The lump did not hurt and it was not broken open or infected, but it just seemed a matter of time before she started suffering painful consequences.

Mammary Adenocarcinoma

There was one confusing, hopeful fact, however. According to Tinkerbell’s mom, Katherine, the tumor had been there for years. Years! Doc Truli knew that metastatic breast cancer in cats usually behaved aggressively – meaning it spread fast and far in the body. But here was TInkerbell with this lump growing for years. Maybe it was not a spreading type of tumor?

“Doc,” said Katherine,” She’s 14, I don’t know if I should put her through surgery at her age.”

How Old is Too Old for Major Surgery?

Many people worry about doing too much invasive medicine or surgery on an older pet. Now, I do not agree that a 10 or 12-year-old cat is old. Or a 10-12 year old Shih Tzu or Chihuahua. A 12-year old Great Dane or Boxer is old, but it all depends of the breed of the patient and their known expected lifespan. Doc has known plenty of 18-20 year-old cats. 14 just didn’t seem that old for Tinkerbell.

Truli Speaking

“I do not agree that a 10 or 12-year-old cat is old,” says Doc Truli.  “An 8-12 year-old cat I call young-old.  12-15 is middle-old.  15 and up is ‘bonus rounds.’  You really have to know your cat.  Are there other diseases that prematurely age your cat, like diabetes or hyperthyroidism or renal insufficiency?  No?  Then why can’t your cat live  20 or 25 years with a little luck?  I believe many cats die too young because their people think they are old and because of the perception that it’s a lot of money to spend on a cat and because of fear that the medicine or surgery will not work, people decline medical care for their cats.  The cats suffer from this medical pessimism.  It’s a shame.”

“If there are no other illnesses apparent on the minimum database testing, and her chest x-rays screening for cancer metastasis are clear, then I believe the surgery is worth it,” said Doc Truli. “Even a benign tumor can grow too large and rupture open, making a painful, infected mess. We need to avoid that outcome for Tinkerbell.”

Minimum Database

Have you heard your veterinarian say “minimum database?”  It means a complete blood count, 25 chemistries of the blood including electrolytes and urinalysis.  The medical standard of care is a minimum database on every sick patient ever time they come to the hospital in order to know the internal status and diagnose correctly.  In cats, many specialists consider the feline leukemia and feline aids virus tests to also be part of the standard-of-care minimum work-up.

In an emergency room, the minimum database has to be fast.  An ER MDB usually consists of electrolytes, BUN, creatinine, blood glucose and PCV (measure of anemia).  The other test take too long when seconds count to save a life.

Tinkerbells’s Big Surgery Day

Tinkerbells’s pre-op lab tests and radiographs were normal. She came for the big surgery day. To help minimize pain and bleeding, her mom elected the upgrade to Laser surgery for her lumpectomy procedure. The Laser cauterizes blood vessels and nerve endings as it cuts with invisible energy beams. The tumor lifted nicely off of the light yellow, slightly greasy subcutaneous fat. The hole sewed up neatly.

A closer view of the Laser at work on the tumor

Then Doc felt a lymph node in Tinkerbell’s armpit. The problem is: normally, you cannot feel cat axillary lymph nodes. Normally they are too small to feel. Doc Truli performed an excisional biopsy of the lymph node, which means removing the whole lymph node for testing to see if it contains cancer cells.

You cannot feel a normal cat armpit lymph node.

Tinkerbell recovered perfectly from surgery and was eating and purring a few hours later.

What is a Biopsy and How is a Biopsy Processed at the Laboratory?

The only way to know for sure if a lump on a cat’s body is cancer is a biopsy. A biopsy means removed a piece of cat and fixing it in poisonous formalin solution and shipping the sample of your cat to the reference laboratory (usually in another state) for a board-certified pathologist to analyze the lump. The lump is sliced into pieces about 1/2 cm across and placed in a special holder called a “Cassette.” Most laboratories will use paraffin (special wax) embedding to preserve the piece of your cat. The gigantic 1/2 room-sized paraffin embedding machine runs for 12 hours to embed the cassette with your cat’s lump in it. Usually these “runs” are done overnight to let the machine work while the laboratory staff enjoys some sleep time at home. (So, if your sample arrives on time for the evening prep and run, you’ll be a day ahead.  If it misses that night, it has to wait 24 hours for the next “run.”)

Tru Tip
Have your veterinarian write “board certified only” on your laboratory request form. In the United States, there is a shortage of board-certified veterinary pathologists, so unless you specify, a board-eligible or resident-in-training may read your sample. Perhaps they will have enough knowledge to help your cat, perhaps not! Pathology is a highly skilled, highly interpretive specialty. You always want the best you can get!

In the morning, the cassettes are taken out of the machine and sent for sectioning. A person physically sits at a machine called a microtome that resembles a tiny table saw crossed with a sewing machine crossed with a razor blade. The technician cuts your cat’s lump into 4-5 millimeter sections. (You can see through 4-5 mm!) They gently lift the 4 mm slice off the machine with tiny steel forceps and float the see-through slice on the surface of a bowl of just-under-boiling hot wax. Once the slice turns color and has interacted with the wax, it is lifted off of the wax and laid flat on a glass microscope slide. After the see-through prepped piece of cat tumor sets and dries, it is stained through a multi-step process and stored for the pathology specialist to examine it under a microscope. (Doc Truli spent a summer at a microtome doing this job to benefit brain cancer research.)

So, next time you wonder why you have to wait “so long” for results, just remember what it takes to get an answer for you and your cat.

This tumor is the "tip of the iceberg," you have to feel around under the skin for these cancers on your cat.

What Are the Options for a Cat After Cancer Diagnosis?

Tinkerbell healed completely after her surgery.   Unfortunately, the results came back “malignant mammary ductal adenocarcinoma with metastasis to a regional lymph node.”  So, on the one hand, that’s a back diagnosis.  We know that no amount of chemotherapy or radiation therapy really helps this kind of cancer in cats.  On the other hand, it also is supposed to grow fast and kill fast, yet she had the lump for years before it grew to a bothersome size.

Tru Tip

If you have an older cat, Vitamin E (no researched dose, some vets use 100IU/day), Omega 3 Fatty Acids at a dose of 180 milligrams of the eicosopentanoic acid (EPA) subcomponent per 10 pounds of cat per day, and Probiotics for cats (get at a vet clinic or a reputable on-line natural products dealer) will only help.  There are very few medical conditions that these supplements will hurt.

We decided to leave Tinkerbell alone.  We boosted her nutrition with kitten food and probiotics, Omega 3 Fatty Acids and Vitamin E, with the idea that good quality nutrition would help her body do whatever it was meant to do to try and stay healthy.  We have no scientific evidence that herbs or other remedies would help in the case of cat mammary cancer.  Plus, being a cat, Tinkerbell did not accept a lot of “messing with.”  It’s a fine line between making a cat do something you know is good for them, and stressing the cat out so much that they get sicker from anxiety and displeasure.

Tinkerbell accepted her new diet and supplements and is going strong all these months after surgery!

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