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Case File

Zola - a Chemotherapy Case Study

by Amy Parsons BVSc MRCVS

 

Zola, a beautiful 8year-old, crossbreed, owned by our Receptionist Mischa is this month’s case story.  Mischa brought Zola to work one day in February of this year with a short history of vomiting and we were asked to take a look. On examination, Zola was bright and alert but had an uncomfortable abdomen. There was a suspicion of a growth but further investigation was needed to determine what was happening in Zola’s abdomen, as when dogs are uncomfortable they can tense their abdominal muscles, thereby not allowing palpation.

Bloods were taken to check if her liver, kidney or pancreas were affected and haematology carried out to assess her red blood cell count, white blood cells and platelet numbers. These results all came back normal so we then needed to image the abdomen to assess the growth that was felt.

We used ultrasonography for this, which is a fantastic tool as it is a non-invasive way of looking at what is going on in the abdomen (or chest as the case may be). We can look at the structure and size of organs and look for changes in their architecture. Patients tolerate it well as they are in a nice dark room, on a comfy bed, being cuddled by nurses! We often use ultrasound in combination with radiographs (X-rays) to gather as much information as possible.  Sadly, the ultrasound confirmed the presence of a 15cm mass, seemingly not attached to any other organ but with a big blood vessel running through it. We attempted to gain a fine needle aspirate (FNA) of the mass guided using the ultrasound, but the results were inconclusive at the laboratory.

 

The next step in finding out what exactly the nature of the mass was to operate. Performing an exploratory laparotomy, or an ‘ex-lap’ as we call it, when we open up the abdomen, has many benefits – it allows us to visualise the entire abdominal cavity, look for abnormalities, attempt removal of growths or importantly, biopsy them if not possible to remove.  A full general anaesthetic is needed but at the Practice we have many monitoring equipment that enables us to keep a close eye on blood pressure, blood oxygen saturation, the amount of carbon dioxide exhaled and heart rate.

Zola was operated on two days after discovering the mass. Pre-operative radiographs were taken to ensure there was no spread to the lungs.  Surgery revealed the mass to be wrapped around the root of the mesentry – the tissue that supplies the whole of the small intestine with its lymphatic drainage and blood supply. There was no way we could remove it and therefore we biopsied it to find out if it was a tumour that could be responsive to chemotherapy.

Zola made a fantastic recovery from surgery, other than diarrhoea, she bounced back in herself and it was now a waiting game for the results of the biopsy sample to come back. Histopathology of the mass revealed the it was lymphoma.  Lymphoma carries a guarded prognosis with sadly very few cases beating it entirely in our canine population. We elected to instigate a ‘high dose COP’ protocol in Zola’s case. This involved, initially, weekly visits to us for administration of vincristine and oral cyclophosphamide – both chemotherapy drugs requiring special handling, and daily administration of steroids at home. This then dropped down to every three weeks. By the fourth week, the mass in Zola’s abdomen was already shrinking and by week twelve, we had achieved remission.

Chemotherapy for dogs raises a lot of questions as people compare the treatment to their understanding of human treatment. Dogs normally cope quite well and do not lose their hair. There are special safety measures which we would discuss with each owner and support them with. We are also proud to be involved with Zoe’s Journey UK who are the Animal Health Trust’s largest fundraising group towards their research into canine cancer particularly lymphoma – for more information see www.zoesjourneyuk.com.

 

Whilst Zola is doing very well, she has had the odd blip, initially she did have vomiting and diarrhoea but we put treatment strategies in place to minimise these effects during ‘chemo weeks’. Mischa would be the first to say that the road to Zola’s recovery has been long, but in her case, the effort and time has definitely been worth it as she is back to her normal, playful self and without these drugs, she would not be with us now.