Multiple myeloma or bone marrow cancer in dogs

Multiple myeloma is the formal name given to bone marrow cancer-a serious but thankfully rare form of cancer that can affect dogs. Whilst the reasons why multiple myeloma might develop and its various risk factors aren’t known for sure, the German shepherd dog breed is the breed that is most likely to develop the condition, which implies that there is a hereditary or genetic element to the disease.

Treatment for the condition can be challenging and is not always effective-but there are options available if your dog is diagnosed with multiple myeloma to manage the condition if treatment is begun in a timely manner.

In this article, we will explain multiple myeloma or bone marrow cancer in dogs in more detail, including how the condition affects dogs, the symptoms to watch out for, and how the condition may be treated or managed. Read on to learn more.

What is multiple myeloma?

Multiple myeloma develops from malignant or cancerous plasma cells in the dog’s bone marrow. Plasma cells are a type of white blood cells that produce a substance called immunoglobin, which is a type of antibody protein that helps the body to fight off diseases and infections.

These cancerous cells ultimately destroy the bones themselves, and of course, a serious and systemic cancer of this type will make your dog very ill and potentially, cause a lot of different symptoms.

Multiple myeloma can also lead to high protein levels in the blood, which can compromise the function of the kidneys, and the cancerous cells produced by multiple myeloma can also spread to other organs and potentially, lead to cancer developing in other parts of the body as well.

What sort of dogs are at risk of developing multiple myeloma?

The reasons behind why any dog might develop multiple myeloma aren’t fully understood, and it is not a particularly common cancer-accounting for around just 7-8% of all canine cancer diagnoses.

However, there is a possibility that the condition is at least partially hereditary in nature, because it appears to develop in the German shepherd dog breed more than any other. It tends to be a disease that affects mature and elderly dogs rather than their younger counterparts, with dogs being aged on average between six and twelve years old at the time of diagnosis.

Males and females are equally likely to be affected, and spayed and neutered dogs have the same risk factors as unneutered dogs.

What are the symptoms of multiple myeloma in dogs?

How severe the symptoms of the condition are and even what symptoms will be apparent depends on how advanced the condition has become, and what parts of the body it effects.

A wide range of different combinations of symptoms may be seen in different dogs, but some of the main and most common signs to look out for include:

• Lameness in one or more limbs-this affects around 50% of dogs with the disease.
• Pain or weakness in the limbs and bones caused by the destruction of the bone tissue is again a common symptom of the condition, affecting just over half of dogs diagnosed with multiple myeloma. This may progress to full or partial loss of use of some parts of the body.
• Lethargy and exercise intolerance.
• Behavioural changes such as being less tolerant than usual, or failing to recognise or follow commands.
• Higher than normal levels of thirst and need to urinate.
• Noisy or laboured breath sounds.
• A high temperature.
• Poor blood clotting ability, so that even small cuts may bleed heavily or for longer than normal.
• Pale mucous membranes.
• A range of different eye problems may accompany the condition, including redness and inflammation, glaucoma or high pressure behind the eyes, and detached retinas.

Because the symptoms of multiple myeloma can be so variable and lead to secondary complications in other parts of the body, diagnosis can be a challenge.

Your vet will take into account the symptoms your dog is presenting with and their medical history, and run a range of tests including blood panels, urinalysis and potentially, take X-ray slides of your dog’s bones and joints to check for lesions and damage. They may also wish to perform a full-body ultrasound examination to check if the condition has infiltrated other organs.

Can multiple myeloma in dogs be treated?

Because multiple myeloma is a unique and far-reaching condition, your vet may wish to consult with or refer your dog to a specialist veterinary oncologist or cancer expert to confirm their diagnosis and determine the best way to proceed.

For cases of multiple myeloma that are caught early and that have not become systemic and spread throughout the body, your vet may treat the localised area with radiotherapy, which in some cases can be effective in eradicating the condition.

However, for more widely spread presentations, chemotherapy may be necessary, although this is usually performed in order to control the condition and reduce the speed at which it spreads rather than successfully curing multiple myeloma altogether.

Dogs with multiple myeloma will also be very susceptible to infections and becoming very ill from what ware usually minor bugs and viruses, and so extreme care must be taken to prevent infection, and treat any infections promptly and aggressively. Pain medications may be required too if the condition can be managed, although often, the decision is made to put the dog to sleep at some point when the condition can no longer be controlled, and has a significant negative impact on the dog’s quality of life.