If your cat has just been diagnosed with mammary cancer, you are likely consumed with questions about what this means for their future.

Mammary cancer in cats is known to be aggressive and malignant, leading many owners to be faced with a quality of life decision at some point.

So what does the diagnosis of mammary cancer mean in our feline friends, and how do you know when it is time to say goodbye?

What Is Mammary Cancer In Cats?

Mammary cancer in cats is a type of cancer that impacts the feline mammary glands.

These tumors develop as a result of abnormal replication of cells within the breast tissue, leading to the development of cancerous masses in the area.

There are multiple types of mammary tumors that a cat can develop, but the most commonly seen are carcinomas.

Each mammary gland can develop a cancerous mass, but the inguinal and thoracic mammary glands seem to be the most impacted.

The feline mammary glands are filled with vessels, which makes it easy for cancer cells to move from one gland to another.

If these tumors are not caught in the early stages of development, they can quickly spread to other regions.

Why Do Cats Get Mammary Cancer?

Experts have not yet pinpointed the exact cause of mammary cancer in cats, but it is believed that exposure to reproductive hormones increases their risk of developing this disease.

A female cat that is not yet spayed will have prolonged exposure to hormones such as estrogen and progesterone, both of which cause the cells in the mammary glands to enlarge.

Once this happens, this makes the cells more at risk of abnormal replication that can lead to cancer.

Intact (not spayed) female cats are 7 times more likely to develop mammary tumors than their spayed feline friends.

Age also seems to be a common factor amongst cats that are diagnosed with mammary cancer, as most seem to be 10 years and older.

Male cats can develop mammary cancer as well, but it is extremely rare.

Can Mammary Cancer Be Prevented In Cats?

There is no way to prevent mammary cancer altogether in cats, but spaying at an early age seems to be the most effective preventative method.

Intact female cats are 7 times more likely to develop mammary tumors, as prolonged exposure to reproductive hormones cause an increased risk of abnormal cell changes.

Not only can spaying your cat help to prevent mammary cancer in the future, but spaying before 6 months of age appears to be most effective.

Cats that are spayed before 6 months of age have only a 9% chance of developing mammary cancer down the line, while cats that are spayed between 7 to 12 months have a 14% chance. (Source – VCA Hospitals)

Obesity appears to play a role in the development of mammary cancer in some cats, so keeping your cat at a healthy weight could be an effective preventative method as well.

Is Mammary Cancer Painful In Cats?

If your cat is ever diagnosed with mammary cancer, you are likely wondering if they have been in any pain.

While we can never know exactly what our furry friends are experiencing, it seems as if the early stages of mammary cancer are not incredibly painful to cats.

These masses can typically be palpated without significant discomfort, causing most to believe they are not in unbearable pain around the clock.

Though not all mammary tumors are painful, many cats will experience pain when these tumors ulcerate or become infected.

An ulcerated tumor is one that grows to the point of breaking through the skin, causing a noticeable wound to develop.

Not only can these open wounds be tender to the touch, but they can become infected when exposed to bacteria.

Once these masses ulcerate, the area can be incredibly painful for your feline friend.

What Are The Symptoms Of Mammary Cancer In Cats?

If your cat has developed a mammary mass, you may notice some changes in their physical appearance and daily behaviors.

Some of the most common symptoms of mammary cancer in cats include:

• Swelling or hardening of the mammary glands
• Redness or warmth of the mammary glands
• Sores on the mammary glands or surrounding areas
• Sensitivity of the mammary glands or abdominal area
• Odor coming from sores on the mammary glands
• Discharge from the nipples
• Frequent licking of the mammary glands, whether a wound is present or not
• Lethargy
• Fever
• Weight loss
• Lack of appetite

If you notice any of the above symptoms in your feline companion, we suggest reaching out to your veterinarian for guidance.

Treatment for mammary cancer is most effective when the disease is caught early, so we suggest contacting your vet from the moment symptoms develop.

How Is Mammary Cancer Diagnosed In Cats?

If your veterinarian suspects mammary cancer in your cat, it is likely because they found a potential mass on the mammary glands during their physical exam.

The presence of any hardening of the tissue or any nodules under the skin can be suspicious to your vet, leading them to pursue diagnostics to get to the bottom of these changes.

First, your vet will palpate this mass in effort to determine its size, if there is any stem, and if any surrounding lymph nodes are affected.

Once they have determined that the mass is truly something to be concerned with, your vet can then perform a fine needle aspirate (FNA).

This involves aspirating a sample of cells from the mass in question, and placing the sample on a microscope slide.

An FNA is not always successful, as sometimes you cannot pull an adequate amount of cells from the mass.

But if the FNA does manage to remove enough cells to examine under the microscope, this can display any cancer cells that are present.

Some vets can examine the slide in their office, but many will choose to send the slide out to a lab to be examined by a veterinary pathologist.

The diagnostic route that offers the most definitive diagnosis is a tissue biopsy and histopathology.

This involves your veterinarian obtaining a tissue sample from the mass itself, and sending the sample into the lab to be examined by a veterinary pathologist.

The pathologist will examine the tissue under a microscope, allowing the vet to not only diagnose the specific cancer that is present, but also predict some of the cancer’s behavior.

This can help your veterinarian determine the staging of the cancer, as well as how likely it is for the cancer to metastasize (spread to other parts of the body).

The methods above are the most effective route in determining if the mass is cancerous or not, but your vet may also perform other diagnostics to determine your cat’s overall health.

They will often suggest performing a chest x-ray before starting treatment, as this can help them determine if any cancer has spread to their lungs.

If your cat has evidence of metastasis to their lungs, this can change the vet’s treatment approach.

An ultrasound can be performed for this same reason, as it will search for any presence of cancer in the abdomen.

In addition to chest x-rays, your vet may also suggest performing some standard blood tests to rule out any metabolic complications.

This is especially important if your cat is over the age of 10, as they are most prone to developing liver and kidney disease.

If your cat is going to be undergoing any aggressive treatment, your vet will need to be aware of any organ dysfunction.

Can You Treat Mammary Cancer In Cats?

Though many cats will eventually succumb to their disease, there are ways to remove the current cancer and offer your cat as much time as possible.

Successful treatment has been proven to give some cats up to 2 years of disease-free time, which is why so many owners choose to pursue treatment.

Surgery is the most effective way to offer a cat as much time as possible.

Your vet can attempt to surgically remove as much of the cancer as possible, as well as the entire chain of mammary glands on the affected side.

This is often essential if the cancer has spread to more than one mammary gland, but it can be done prophylactically when the cancer has not yet spread as well.

If the cancer is present in the mammary glands on both sides, both chains can be removed if the area allows for it.

This may not be possible if there is not enough skin to close the incision, but if this is the case, another surgery can be performed to remove the rest of the cancer once the initial incision has healed.

Once the mass has been surgically removed, many vets will recommend chemotherapy due to how likely metastasis is with mammary cancer.

The combination of surgery and chemotherapy typically offers the best disease-free intervals, especially for the cases that are caught early on.

Every case will vary, so we always suggest trusting your vet’s guidance when determining the best treatment plan for your cat.

There are so many factors to consider when battling this aggressive form of cancer, and your vet is the only one that can assess the full picture.

Does Treatment Always Work?

Mammary cancer treatment is typically effective in offering a cat more time.

Only a small percentage of cats will go into remission after undergoing treatment for their cancer, but many will at least be offered extra time and pain relief after pursuing surgery or chemotherapy.

Though treatment may not cure many cats of their mammary cancer, it can offer them more time at their beloved owner’s side.

Prognosis Of Mammary Cancer In Cats

The standard prognosis of mammary cancer in cats will vary based on how progressed the cancer is at the point of diagnosis.

Most cases of mammary cancer have a guarded prognosis in our feline friends, as the cancer has such a high rate of metastasis.

Though most cases are given a guarded diagnosis, there are certain factors that seem to offer a cat more time.

Less Than 2cm In Diameter: Up To 4 Years

If the mammary tumor is detected and removed when it is less than 2cm in diameter, most cats appear to have a survival time of up to 4 years.

3cm In Diameter Or Larger: 6-8 Months

If a mammary tumor is detected and removed once it has reached 3cm in diameter or larger, their standard survival time decreases to anywhere from 6-8 months.

As you can see, early detection is essential in offering your cat the longest survival time. 

If the cat has any lung involvement when they are diagnosed with mammary cancer, they typically have up to one month of survival time.

Some vets will not pursue any aggressive treatment at this point, but rather offer your cat palliative care until it is their time to go.

It’s important to keep in mind that over 60% of mammary tumors in cats will return within 12 months of their initial diagnosis and removal.

This is considered an aggressive form of cancer, so you will need to monitor your cat closely throughout each moment of their recovery.

Maintaining a close relationship with your veterinarian is essential in not only offering your cat the longest survival time, but also catching any developing tumors quickly.

When To Euthanize A Cat With Mammary Cancer

As you can see from the information we discussed above, most cats will eventually succumb to their mammary cancer.

Due to this possibility, it’s important to be aware of the signs of a cat suffering from their disease.

To help you better understand when it may be time to say goodbye to your cat with mammary cancer, let’s list a few behaviors to be on the lookout for.

If your cat is experiencing any of the symptoms or behaviors listed below, it may be time to have a quality of life discussion with your vet.

These symptoms include:

• Significant weight loss
• Lack of appetite
• Disinterest in things they once enjoyed
• Chronic weakness or lethargy
• Metastasis to the lungs
• Changes in breathing, or difficulty breathing
• Painful, ulcerated masses on the mammary glands

If your cat is experiencing any of the above complications, it may be time to discuss the possibility of euthanasia with your veterinarian.

Your vet may be able to offer a last attempt at aggressive treatment, or they may support you with the decision of saying goodbye.

Every situation is different, so it’s best to seek support from your cat’s veterinary team.

Final Thoughts On Mammary Cancer In Cats

Mammary cancer is an invasive and aggressive cancer seen in some unlucky feline friends.

Early detection is essential in offering your cat the longest survival time, so we suggest having them seen if you ever notice any strange lumps and bumps.