Bone Cancer in Dogs - What Is It and What Can Be Done?

Hearing that your dog may have bone cancer is devastating news. It’s an emotional and overwhelming time for owners and it can be difficult to know where to start or what steps to take next. Understanding the condition can help pet parents feel more prepared and empowered to make the best decisions for their beloved dogs. This article is here to help by explaining what bone cancer is, the signs to look out for, how it’s diagnosed, and what treatment options are available.

What Is Bone Cancer in Dogs?

Bone cancer in dogs is a serious condition that affects the structure and strength of the bones. It tends to be quite aggressive, often spreading to other parts of the body – especially the lungs. It can be incredibly painful and may present as sudden lameness, swelling, or even a fracture without major trauma. Although osteosarcoma is the most frequent type we see, there are other, less common forms of bone cancer too. The most common type is called osteosarcoma. This type of cancer starts in the bone itself, rather than spreading there from somewhere else in the body. Osteosarcoma can be very aggressive. It tends to damage the bone where it begins and, unfortunately, it often spreads very quickly to other areas – most commonly the lungs and sometimes other bones. Because of this, it’s considered a serious and potentially life-limiting condition.

While osteosarcoma is by far the most frequently diagnosed, there are other, less common types such as chondrosarcoma, fibrosarcoma, and haemangiosarcoma. These can behave a bit differently and are sometimes less aggressive, but in this article, we’ll focus mainly on osteosarcoma because it’s the one we encounter most often in practice.

Which Dogs Are Most at Risk?

Bone cancer can affect any dog, but certain breeds and types of dogs are at much higher risk.

Large and giant breeds are most commonly affected, such as Great Danes, Rottweilers, Greyhounds, Dobermans, Irish Wolfhounds, and Saint Bernards.

Middle-aged to older dogs are more commonly affected, typically between 6 and 10 years old. However, it can occasionally be seen in younger dogs too.

Males are usually more commonly affected than females.

Dogs that have suffered from previous bone injuries or fractures repaired with metal implants may have a slightly increased risk, although this is still relatively rare.

Where Does Bone Cancer Typically Develop?

Osteosarcoma can develop in any bone, but it has some preferred locations. It tends to affect the bones of the limbs – this is known as appendicular osteosarcoma.

The classic phrase to remember is “away from the elbow and near the knee,” meaning it commonly occurs:

In the distal radius (just above the wrist)

In the proximal humerus (near the shoulder)

In the distal femur (above the knee)

In the proximal tibia (below the knee)

It can also develop in the bones of the spine, skull, ribs, or pelvis – this is known as axial osteosarcoma – but this is less common.

What Are the Signs of Bone Cancer in Dogs?

The signs of bone cancer can sometimes be subtle at first, which can make early diagnosis challenging. Common symptoms include:

Lameness – often persistent and progressive, and not improving with rest or pain relief

Swelling – a firm, sometimes painful swelling over the affected bone

Pain – your dog may flinch, whimper, or be reluctant to use the affected leg

Reluctance to exercise – your dog may be less keen to walk or play

Lethargy

Loss of appetite and weight loss in more advanced cases

Occasionally, the affected bone may become weakened so much by the cancer that it fractures – this is known as a pathological fracture. This usually causes sudden, severe lameness and is a veterinary emergency.

If you notice any of these signs, it’s important to have your dog checked by your vet as soon as possible. Early diagnosis can make a big difference to your dog’s quality of life and the options available.

How Is Bone Cancer Diagnosed?

Your vet will start by taking a full history and performing a thorough clinical examination. If bone cancer is suspected, the next steps usually include:

X-rays (Radiographs)

X-rays are often the first diagnostic test. Osteosarcoma has a fairly characteristic appearance on x-rays, showing a destructive, moth-eaten pattern in the bone, and sometimes new bone production around the tumour.

It is important to note, x-rays alone can’t provide a definitive diagnosis. Other conditions, such as bone infections (osteomyelitis), can sometimes look similar.

Biopsy

The most accurate way to diagnose bone cancer is by taking a biopsy – a small sample of the bone tissue – and sending it to a laboratory for analysis. This confirms the type of cancer and helps guide treatment decisions.

Depending on the location and the circumstances, your vet might recommend:

A needle biopsy (a small core of tissue taken with a special needle)

An open biopsy (a larger sample taken surgically)

Blood Tests

Blood tests are often performed to assess your dog’s overall health and check for any underlying problems that might affect treatment.

Chest and abdominal X-rays or CT Scan

Because osteosarcoma commonly spreads to the lungs, and areas in the abdominal cavity, x-rays or a CT scan of these areas are usually recommended to look for evidence of metastasis. This helps your vet to stage the disease – meaning they can find out how far it has spread. This is crucial in helping you and your vet decide on the best treatment plan.

Ultrasound

Although ultrasound doesn’t directly examine bones, it’s incredibly useful in checking for signs of cancer spreading to internal organs, such as the liver, spleen, or kidneys. It also allows your vet to assess nearby lymph nodes for any abnormalities. Ultrasound can also be a valuable tool when preparing for surgery or chemotherapy, as it helps assess your dog’s overall health status. If tissue samples need to be taken, through a fine needle aspirate or biopsy, ultrasound can be used to guide the needle to ensure it’s done safely and accurately.

What Treatment Options Are Available for Bone Cancer in Dogs?

Unfortunately, because osteosarcoma is such an aggressive cancer, treatment is usually aimed at prolonging the time the dog has while ensuring they remain comfortable and enjoy a good quality of life, rather than seeking a cure.

Treatment options include:

Surgery

Amputation of the affected limb is the most common surgical treatment for appendicular osteosarcoma. Although this sounds drastic, most dogs cope extremely well on three legs, especially with good pain management and rehabilitation.

Removing the tumour significantly reduces pain and improves quality of life. However, it’s important to remember that surgery alone rarely cures osteosarcoma – it addresses the primary tumour, but microscopic metastases are usually already present elsewhere in the body.

For dogs where amputation isn’t possible (for example, if they have severe arthritis, or other orthopaedic issues, or they may not be a suitable patient for a general anaesthetic), limb-sparing surgery may be an option. This involves removing the tumour and replacing the missing bone with grafts or metal implants. It’s a highly specialised procedure and not suitable for every case.

Chemotherapy

Chemotherapy is often recommended after surgery to tackle any microscopic spread of cancer that cannot be seen on imaging. It doesn’t typically cause the severe side effects seen in humans – dogs generally tolerate chemotherapy very well, with minimal impact on their daily lives. Common chemotherapy drugs for osteosarcoma include carboplatin and doxorubicin. Chemotherapy can significantly extend survival times compared to surgery alone.

Palliative Care

In some cases, owners may choose palliative care instead of surgery or chemotherapy. This focuses on managing pain and maintaining quality of life for as long as possible. Options for palliative care include:

Pain relief – using strong painkillers such as opioids, NSAIDs, and nerve pain medications

Palliative Radiotherapy – sometimes used to relieve pain

Bisphosphonates – medications that can help reduce bone pain and slow bone destruction

Your vet will work closely with you to tailor a plan that keeps your dog as comfortable as possible.

What Is the Prognosis for Dogs with Bone Cancer?

Sadly, the prognosis for osteosarcoma is generally poor, but it varies depending on the treatment chosen.

With amputation alone, average survival time is around 4 to 6 months.

With amputation and chemotherapy, average survival time can extend to around 10 to 12 months, with around 20% of dogs living longer than 2 years.

Without treatment, survival time may only be a few weeks to a couple of months, depending on the severity of the disease.

Each dog is different, and some dogs respond better than others. Some exceptional cases even survive significantly longer than expected.

Coping With a Diagnosis of Bone Cancer

Facing a diagnosis of bone cancer in your dog is heart-breaking. It’s completely normal to feel overwhelmed, frightened, and unsure of what to do.

The team at your vets will be there to support you every step of the way. They will help you understand your options and guide you towards the choice that is right for you and your dog.

Sometimes, the kindest decision is not to pursue aggressive treatments but to focus on making your dog’s remaining time as happy and comfortable as possible. There is no “right” answer – only the answer that feels best for your pet and your family.

You can get support from the Blue Cross Pet Loss Support service if you need to talk.

Final Thoughts

Bone cancer in dogs is a serious and aggressive disease, but there are treatment options available that can significantly improve your dog’s quality of life and potentially extend the time you have together.

Whether you pursue surgery, chemotherapy, palliative care, or a combination of approaches, your decision will always be made with your dog’s best interests at heart.

If you’re ever faced with this diagnosis, don’t hesitate to reach out to your vet with any questions, or worries, or simply for support. They will always be happy to help.