As a vet, it is never a nice feeling to have to tell an owner that you think their pet might have cancer. Dogs suffer from a variety of different cancers just like humans do. And some are more treatable than others.
Veterinary treatments have come a long way in the last 20 years, and one of the fields that has shown the greatest advancement is oncology. We can treat many cancers better and with greater success now than ever before. There are whole units at referral centres dedicated to oncology and offering your pet the best treatments around.
Lymphoma is one of the most commonly diagnosed cancers in domestic dogs and, fortunately, one of those that we have a lot of options with how to treat.
What is Lymphoma?
Lymphoma is a cancer of the body’s lymph nodes and lymphatic system, which is the system that is key in the ability to fight infections and crucial in the reservoir of immunity to all mammals.
This particular cancer originates in cells called lymphocytes which are responsible for the ability of the body to mount a response to invaders like bacteria, viruses and toxins. These cells travel all over the body, which means that lymphoma can present with signs all over the body.
What dogs get Lymphoma?
It most commonly affects dogs in middle to older age groups, although can affect them at any age.
Whilst any breed of dog can get it, there are several breeds that are more susceptible than others, with a possible genetic link meaning that when getting a puppy it is always worth doing your research where possible to see if any previous litters and relatives have had the disease:
- Golden Retrievers
- Basset Hounds
- St Bernards
- Scottish Terriers
- Airedale Terriers
Are there different types of Lymphoma?
Yes is the short answer. Whilst lymphoma attacks the same systems, it can present in different ways.
There are four commonly recognised variations of lymphoma in dogs.
Multicentric lymphoma. This accounts for the vast majority of cases (80-85% of cases) and affects the lymph nodes all over the body.
Alimentary lymphoma. This affects the lymph nodes of the gastrointestinal tract, so may not present with the stereotypical swollen lymph nodes on the body’s extremities like multicentric lymphoma.
Mediastinal lymphoma. This a very rare (I have only ever seen one case) and affects lymph tissues in the chest so is often diagnosed on radiographs.
Extranodal lymphoma. Incredibly rare but affects non-lymphoid tissues. (I have never seen a case).
“The most common presenting sign for lymphoma in dogs is a swelling of the lymph nodes.”
What do I look for?
The most common presenting sign for lymphoma in dogs is a swelling of the lymph nodes. These lymph nodes are dotted all over the body, but the most common ones to swell in cases of lymphoma are shown in the image at the start of this article referred to as:
- Submandibular LN
- Prescapular LN
- Axillary LN
- Inguinal LN
- Popliteal LN
Swellings can be felt in one or all lymph nodes depending on how far the cancerous cells have travelled around the body. However, it is important to note that not all lymph node swelling are signs of cancer-they can just be a response to inflammation and infection. So, every time you feel a swelling it is not cause for panic, but it is important to monitor and to consider having samples taken.
As with all conditions, symptoms are almost always related to the organ that is affected. There are other things to look out for like vomiting, diarrhoea, loss of appetite, lethargy, weight loss, swellings, increased drinking, increased urination, increased breathing rate and reduced exercise tolerance.
How do we diagnose Lymphoma?
As vets, we always want a diagnosis. This is the case for several reasons: it confirms that we are treating your pet for the right condition, but also allows us to give you vital information about the prognosis (outlook) for your pet.
Diagnosis of lymphoma can be relatively straight forward in many cases, most vets will offer you a fine needle aspirate as a first approach as this is minimally invasive and means there is often very little stress for your pet-many of them never even feel the needle going in. We take a needle and insert it into a swelling to collect some of the cells. We can assess the cells under a microscope and send samples off to a lab for a full assessment.
Sometimes, if this method is unsuccessful, it is necessary for us to perform a general anaesthetic to collect a biopsy from the mass, or we can remove the mass completely in order to get a more accurate sample and allow for a more accurate diagnosis.
You can wait for the results from these tests, or in some cases, the decision is made to take some radiographs and have an ultrasound scan to assess the other lymph nodes in the chest and the abdomen as well as organs that form part of the lymphatic system like the spleen.
It is almost always the case that your vet will take a blood sample to assess the general health of your pet and get vital information as to the number of various cells affected by the lymphoma. This is important as it allows us to monitor these levels with repeat samples later on in the process if you go ahead with treatment for the condition.
My dog has Lymphoma, what is the outlook?
Lymphoma is a condition that, sadly, we can’t cure in most cases. However, it is often one of the more treatable cancers, meaning that it is more likely that we can achieve remission in your pet.
This means that, while the cancer is still there, it is not advancing and not causing clinical signs-this means that when in remission, your pet can often lead a full and normal life.
Like with most conditions, there is a sliding scale for severity of lymphoma and the point of diagnosis also has an impact on how long they will live after diagnosis. This again highlights the need for all the diagnostic tests as well as ongoing repeat tests if they are in remission to monitor any disease progression and allow us as vets to intervene as soon as possible.
How do we treat Lymphoma?
As with many conditions, the treatment options for lymphoma are varied in both success and also cost. However, the good news is that there are generally treatment options to suit all budgets.
The most basic and cost effective treatment option is to use steroids alone. When used alone steroids work in a good number of cases but not in all and can help to increase life expectancy by up to three months.
The next step up in treatment options is chemotherapy. The aim of chemotherapy is to get your dog to a stage where the disease is in remission, meaning that they no longer require treatment at that time. Cancerous cells tend to have a higher rate of growth than normal cells meaning that the chemotherapy can be very targeted towards these cells and spare the bodies normal cells.
There is a common misconception that people think chemotherapy involves your dog being hooked up to drips and pumps in hospital and, while that is the case for some treatments, there are others than involve tablets only that can be done at home and so reduce the number of visits to the vets that are needed.
There are various different chemotherapy strategies used by vets to treat lymphoma, and regular blood tests will be taken to see how the disease is changing.
If your dog achieves remission then treatments can be stopped and restarted at a later date if, and more likely, when the disease returns.
Many cases that are successfully treated will go on to have an extra 12-18 months of normal life.
What if treatment doesn't work or the Lymphoma comes back?
The sad reality is that, as mentioned above, lymphoma can often return and, in many cases is more aggressive on its return. Chemotherapy can be restarted and may buy more time, but the important factor to always have at the centre of the issue is your beloved pet’s quality of life. This is a conversation that can, and should, be undertaken with your veterinary team so that you can make informed and sensible decisions that have their welfare at its core.
It is never nice to get the horrible news about lymphoma for your pet, but remember that in many cases there is a lot that can be done to give your pet excellent quality of life for up to 18 months and in exceptional circumstances more than that. The important thing is to work closely with your vet to make sure that you do the best for your pet at all turns.
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