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Jack’s Story
by Andy Fullerton BVSc(Hons), MRCVS

(Canine Lymphoma)

Jack Fullerton is a 12-year-old male Border Collie who came to see us in September at our Yatton Surgery. He had been generally duller than normal and was very stiff and slow.  Rather than blaming old age and arthritis, Mrs Fullerton had a feeling something wasn’t quite right.  When we checked Jack over we spotted that his lymph notes were slightly enlarged. Jack was booked in to X-ray his spine and hips to rule out arthritis as the cause of his “slowing down” and at the same time remove one of his lymph nodes to send of to the lab.  The X-rays did show a problem with Jack’s spine called spondylosis; this is where a bridge of new bone fuses two vertebrae together and is common in old animals resulting in a reduction in mobility.  Although it is easy to say, “job done, case solved” at this stage, we were still concerned about the reason for Jack’s enlarged lymph nodes.  The spondylosis would have been there for some time and may not be the reason for the recent slow down. 


Jack’s results came back very quickly and unfortunately were not good news.  The diagnosis was High Grade Canine Lymphoma (see below for more info).  Even in the 3-4 days between Jack’s surgery and his first check-up it was evident that his lymph nodes had got bigger (especially the ones in front of his shoulders).  Time was of the essence at this point and Mrs Fullerton not only had to come to terms with the news that Jack had lymphoma but also had to decide whether or not to go for chemotherapy.  After long discussions of the advantages and disadvantages we decided to start chemotherapy. 

For the first 2 months Jack needed weekly intravenous (into a vein) injections of a drug called vincristine.  At the same time Mrs Fullerton had to give Jack 2 other drugs in tablet form, initially every day and then every other day after the first week.  Jack responded perfectly to the chemotherapy and his lymph nodes were so small by the end of the first week that we couldn’t feel them any more!!  He was in remission!!!!  However, everything was not plain sailing in the first 2 weeks.  Not only do these drugs suppress the tumour, they also suppress bone marrow turn over and hence the production of normal white blood cells.  This can leave dogs susceptible to infection.  The first weekend after his chemotherapy Jack had a funny turn and was very weak.  Mrs Fullerton rushed him to us that day and we found that his temperature was 105.5 of (HIGH!!).  Jack had a secondary infection as the drugs had suppressed the immune system too much and we therefore stopped chemo for 4 days until his next injection was due.  We also gave jack 2 different antibiotics in order to fight the infection and true to form he was back to normal the next day!!!  After checking his white blood cell count was OK we re-started chemo.  The next two weekends following chemo Jack lost his appetite and would be a bit off colour but nowhere near as bad as that first weekend.

Jack hasn’t looked back since!  His bone marrow became used to the drugs and it is now 3 months since the start of chemo.  Jack is only having the injection and oral medication every other week now.  In 5 months he will then only need chemo every third week.  Mrs Fullerton swears that Jack is a new dog and full of life! He loves his walks on the Moors again and his appetite is ferocious!  It’s well known within the practice that he likes his treats when he comes in for chemo!!!!  Mrs Fullerton takes every day as it comes and treats it as another day with Jack she wouldn’t have had.  Although chemo is not a cure for Jack’s lymphoma he has had an amazing 3 months and long may his good health continue!  He always puts a smile on our faces when he visits the practice and is a shining example of how well chemotherapy can work in animals.


Canine Lymphoma

Canine lymphoma is one of the more common tumours we see in dogs (7-24% of all canine tumours).  This is a cancer of the white blood cells, specifically lymphocytes.  Lymphocytes normally “patrol” the body via the blood system and help coordinate the fight against infection.  Lymphocytes are produced in the bone marrow and normally live for about 30 days before they self-destruct and are re-absorbed into the body.  They circulate in the blood and are called upon when infection attacks the body.  Each part of the body has a lymph node to which it “drains” and lymphocytes along with other white blood cells will also drain to these lymph nodes.  Think of lymph nodes as the headquarters for white blood cells.

In canine lymphoma the regulation of production is lost and or the cells lose their programmed lifecycle (i.e. live longer), this results in lymphocytes overwhelming the other blood cells. The disease can be classified with respect to where it is in the body.  The most common type of lymphoma in dogs is multicentric lymphoma, which involves all lymph nodes (approximately 80% of canine lymphoma cases).  The other (less common) types include the spleen, skin, chest or gastrointestinal tract (gut). 

For the purposes of this article we will focus on multicentric lymphoma, as it is the most common.  The disease starts as an enlargement of an individual lymph node along with a raised white blood cell count on blood tests.  This is usually unnoticed and the disease therefore progresses to other lymph nodes eventually resulting in enlargement of all superficial lymph nodes.  As the disease progresses the dog will become more lethargic (tired), lose weight and will start to lose his appetite.  This disease is fatal without any treatment.

Diagram to show the lymph nodes that commonly enlarge during lymphoma:

 

Low Grade Lymphoma: This is slow in onset and will take longer to progress but unfortunately does not respond as well to chemotherapy when compared with high-grade lymphoma.

High Grade Lymphoma: This is fast in onset but if caught early will respond well to chemotherapy.


How do we diagnose the disease?

The disease is diagnosed by removing or taking a biopsy of an enlarged lymph node.  This is then sent off to a lab where they will look at what is in the lymph node.  In lymphoma the lymph node architecture is lost and replaced with sheets of lymphocytes.  This pathologist can then assess/grade the lymphoma i.e. low or high grades. 


How can we treat Lymphoma?

The main treatment of lymphoma is chemotherapy.  Many people will refuse chemo for their dogs as they are worried about the well known side effects seen in human medicine such as nausea, hair loss, lethargy etc.  In veterinary medicine we have to balance the benefits of chemo with the side effects and find a happy medium.  Unlike humans, dogs are unable to understand why the side effects are happening to them and therefore it would not be fair to use chemotherapy if their quality of life was going to be poor during treatment.  In order to reduce the side effects we administer the drugs at a lower dose resulting in the disease retreating and enhancing quality of life.   This will never be a cure for lymphoma but will prolong lifespan for up to 9-12 months or more!  During this time they will have very few side effects from the drugs and will be able to live life to the full.