Get

In Your Inbox

Catster is reader-supported. When you buy via links on our site, we may earn an affiliate commission at no cost to you. Learn more.

Bone Marrow Cancer in Cats: Our Vet Discusses Signs, Causes & Treatment

cat in the clinic with veterinarian and owner

We often think of cancer as a lump or bump that pops up somewhere on our cat’s body. We can typically see and feel it. However, with bone marrow cancer in cats, there often isn’t anything to look at. Instead, we have to rely on other signs that can look similar to those of other kitty illnesses. This makes bone marrow cancer difficult to deal with. Fortunately, the more you understand it as an owner, the sooner you can seek veterinary care and improve the outcome for your feline friend.

divider 3 paws

What Is Bone Marrow Cancer in Cats?

Bone marrow is the spongy interior of bone, encased by the hard mineralized exterior. It’s rather spectacular because it’s basically the manufacturing site of blood. Red blood cells, white blood cells, and platelets are made and released in bone marrow, all with vital functions in the body. Bone marrow cancer in cats occurs when cancer cells decide to settle in the bone marrow, disrupting the normal flow that provides these necessary blood cells. Sometimes, certain types are overproduced so there is an imbalance in the number of all blood cells produced, or abnormal blood cells that don’t function properly are produced. Either way, it means bad news for all the functions of the body that rely on blood cells to perform.

Bone marrow cancer takes a few different forms in cats, including multiple myeloma, lymphoma, and metastatic cancers that have traveled from other parts of the body and found refuge in the bone marrow. All these types can produce similar signs.

vet holding sick cat
Image Credit: megaflopp, Shutterstock

What Are the Signs of Bone Marrow Cancer in Cats?

Rather than a direct lump or bump, bone marrow cancer can produce rather vague signs that could be indicative of several illnesses. These signs may include:

  • Weakness, lethargy, depression
  • Weight loss
  • Loss of appetite
  • Lameness
  • Changes in behavior, such as hiding and vocalizing
  • Increased water consumption
  • Bloody urine or feces
  • Unexplained bleeding

Your cat may also have a history of frequent infections, you may notice a lump or two in other areas of the body, and they may show pain by vocalizing more, hiding more, and not wanting to move as often or be touched.

sick siberian cat
Image Credit: Olesya_Alexandrova, Shutterstock

What Are the Causes of Bone Marrow Cancer in Cats?

Fortunately, bone marrow cancer in cats is relatively rare. Unfortunately, we can’t point fingers at a specific cause. Instead, bone marrow cancer appears to be caused by the same things that cause other types of cancer, including genetics, exposure to chemicals and irritants like smoke and toxins, and other illnesses.

Infections with feline leukemia virus and feline immunodeficiency virus may also increase a cat’s chances of developing bone marrow cancer and other blood abnormalities due to the factors associated with any other type of cancer, including UV exposure and certain vaccines, as these can metastasize to the bone marrow.

To do your best to prevent bone cancer in cats, be sure your kitty is up to date on vaccinations, avoids mingling with sick cats, and is exposed to the least amount of environmental toxins possible. Regular veterinary care can also play a role, as your vet can help monitor your cat’s health in ways that you won’t be able to at home in order to hopefully catch any illnesses before they become big problems.

If you need to speak with a vet but can't get to one, head over to PangoVet. It's an online service where you can talk to a vet online and get the advice you need for your pet — all at an affordable price!

PangoVet_Mention-in-Content for PangoVet2 save money

How Is Bone Marrow Cancer in Cats Diagnosed?

You will likely notice that your kitty is acting strangely, so you may decide to monitor them for a few days and then bring them to the vet for the reason that they’re just not acting right. Maybe you’ve seen a change in appetite or energy level or even weight loss, or perhaps their frequent illnesses have you worried. Either way, bone marrow cancer likely isn’t the first issue that comes to mind.

It probably isn’t the first issue on your vet’s mind either, so they’ll have to rule out other causes of the signs that you’re seeing by doing a thorough exam, asking you questions, and running tests. Blood work may reveal abnormalities in the blood cells, including differences in sizes, shapes, and numbers. It will also give them insight into how your cat’s organs are functioning. An X-ray may be taken to check bone structure and to look for tumors in other areas. Ultrasound may be helpful for this too.

If the results of these tests put your veterinarian on the bone marrow cancer track, they may perform a urinalysis to check for Bence-Jones proteins, which can be indicative of bone marrow cancer. From there, a sample is necessary for a definitive diagnosis.

vet-working-in-laboratory
Image Credit: Kzenon, Shutterstock

How Do I Care for a Cat With Bone Marrow Cancer?

In many cases, bone marrow cancer may not be able to be cured. Treatment aims to make your kitty feel as comfortable as possible and prolong their quality of life. How your vet goes about this will depend on the type of bone marrow cancer your cat has, their overall health, and whether the cancer has spread.

Treatment options may include surgical removal if the cancer is isolated or chemotherapy and/or radiation if it’s not. However, with these types of treatments, it’s best to weigh the outcome with the side effects.

Supportive care may also be offered in the way of corticosteroids to help suppress cancer activity, pain medications to help your cat feel better, and antibiotics to treat secondary infections due to decreased immune function. Cats may require hospitalization, especially in the early phases of treatment, to make sure that they are handling everything well and that side effects aren’t too severe.

Bone marrow cancer in cats is tough to get rid of, especially if it comes from a tumor that has metastasized. So, expect to have an in-depth conversation with your vet about your cat’s quality of life and the potential for prolonging that quality or the potential for treatments’ side effects to negatively affect it.

On the home front, whether you choose treatment or not, you’ll need to protect your cat from possible illnesses, as they will likely have a decreased ability to fight diseases. This means keeping them away from critters that haven’t been vaccinated, keeping them inside, and providing them with a high-quality diet and a safe place to rest.

You may have to get creative in order to boost your cat’s appetite, such as offering canned food or changing flavor options. Be sure your kitty is drinking water enough to prevent dehydration, and give them plenty of one-on-one time with plenty of love and affection.

divider 2 cats

Frequently Asked Questions (FAQ)

What Is the Prognosis for Bone Marrow Cancer in Cats?

How long your kitty lives with bone marrow cancer will depend on several things, including the type of cancer, stage, and their overall health. It can also depend on the treatments taken and how they respond to those. While a treatment can prolong a cat’s quality of life for a little while, the long-term prognosis for bone marrow cancer is fairly poor. It’s unlikely that your cat will be completely cured of bone marrow cancer, but they can at least live a comfortable life under your care.

vet examining the sick cat with stethoscope
Image Credit: 4 PM production, Shutterstock

What Are the Early Warning Signs of Bone Marrow Cancer in Cats?

Unfortunately, there’s no specific sign of bone marrow cancer. Instead, what you’re likely to see is your kitty acting a bit off. Maybe you can’t put your finger on it directly, but you just know something is up. They may not be eating as much, maybe they’re drinking a little more, or they’re not as rambunctious as before. Perhaps they’ve taken to hiding or have started crying out more commonly. Either way, any change in your cat’s habits or behavior warrants a veterinary visit.

divider 1 paws

Conclusion

Bone marrow cancer is relatively rare in cats, and it can be difficult to diagnose early on due to its ambiguous signs. It also isn’t likely to be cured, but that doesn’t mean a cat can’t live with a high quality of life for as long as possible with treatment and supportive care. Speak to your veterinarian about any abnormal signs or behavior changes that you’re seeing in your cat in order to catch issues early and afford the best possible outcome.


Featured Image Credit: Sata Production, Shutterstock

Want content like this delivered to you?

Sign Up For Our Newsletter

News, insights, expert advice, and everything cat

* By submitting, you agree to our Terms & Conditions and Privacy & Cookies Policy.

How useful was this post?

Click on a star to rate (you can leave written feedback after clicking submit)

Help us improve Catster for pet parents!

Your feedback really matters.

What did you like about this post? Also how can we improve it?

Join the conversation

Leave a Reply

You’re very welcome to leave a comment or question. Please know that all comments must meet our community guidelines, and your email address will NOT be published. Let’s have a positive and constructive conversation.

Talk With A Vet Online

Peace of mind,
anywhere, anytime

Affordable vet advice

11 Best Cat Scratchers of 2025 – Reviews & Top Picks

Our beloved cats scratch for all sorts of reasons, so it makes perfect sense to make sure you have at least one type...

Why Is My Cat Licking the Carpet? 5 Vet-Reviewed Reasons

If you have a cat, you’ll already know how quirky and unpredictable they can be. Unfortunately, when our cats have something going on,...

How to Keep Cats Away From Bird Feeders: 6 Proven Methods

Bird feeders can add color and life to your yard or garden, but they can be a death trap if you have skilled...

Ascites in Cats (Abdominal Fluid Buildup): Our Vet Explains Signs, Causes & Care

Your feline friend’s round belly is often cute and endearing. While that roundness is typically the result of too many treats (which isn’t...

More related

So Phresh Cat Litter Review of 2025: Recalls, Pros & Cons

Review Summary If you’re looking for an effective cat litter brand at an affordable price, it’s worth taking a look at So Phresh....

Can Cats Eat Tacos? Vet-Verified Facts & FAQ

We all know about taco Tuesdays because who doesn’t love tacos right?! It is tempting to want to share your meal with your...

An Introduction to Raphael in Eight Questions (and Answers)

Welcome to the Wednesday Cats of Catster! Every week, we share a story from one of our cat-loving Catsters. This week is about...

10 Best Cat Scratching Posts in Australia in 2025 – Reviews & Top Picks

Cat scratching posts are a great way for cats to burn off some energy and frustration while offering them an abrasive surface that...

Keep reading

How to Socialize Your Kitten: 6 Vet-Approved Methods

It’s always exciting to bring home a new kitten. Not only are they incredibly cute, kittens are also full of personality and charm. Of course, you want your cute little kitten to relate well with you and the people you...

two kittens playing together outdoors

Why Does My Cat Stare at the Wall? Our Vet Discusses Common Reasons & What to Do

There are many things our cats do that confuse and confound us, and one behavior that can be quite concerning is when they start staring intently at a wall. Are they sleeping with their eyes open? Do they see something...

cat staring at the wall

Do Cats Think Dogs Are Cats? Vet-Reviewed Science & Info

Even though cats and dogs have a negative association, many get along very well. If you have dogs and cats, you probably already know that! Seeing cats and dogs interact can range anywhere from cute to hilarious, and sometimes, it...

Cat and dog together on sofa indoors

Does My Cat Have Asthma Or a Hairball? Vet-Approved Main Differrences

If your cat has been coughing and gagging, you may wonder about the possible causes, including asthma and hairballs, and if there’s a way to figure out the difference. While asthma and hairballs can cause cats to cough, the two...

vet giving medicine to a cat

How to Keep Cats Away From Poinsettias: 7 Vet-Verified Ways

With the holidays comes decorating, whether hanging up pretty baubles or keeping a few lovely holiday plants around. But as a cat owner, you should be careful with what you’re decorating with, especially regarding plants. Our feline friends greatly enjoy...

Cat biting plant poinsettia

Why Is My Cat Is Sitting Like a Person? Is That Normal?

Most cat owners can agree that there’s never a dull moment in a feline household. No matter your cat’s personality, they’re always up to their brand of mischief or mayhem. Plus, they spend a lot of their time performing actions...

Scottish fold cat sitting like a human

Can Cats Eat Frosting? Vet-Reviewed Facts & FAQ

Frosting is a delicious topping on cupcakes, cakes, and cookies. With its main ingredients of sugar, butter, and cream, it’s a sweet, tasty addition that is sure to make anyone want more. If you’re a cat parent, you’ve probably encountered...

Can Cats Eat Frosting

What Is Cat Imprinting? Everything You Need to Know

Cat imprinting is a complex psychological and social bond between a cat and their human. It is challenging to describe the process but easy to see the signs. Essentially, a cat imprinted on you has accepted you as a member...

bengal cat gives a high five paw to the owner