April 14th, 2023
Webinar Review: Feline Lymphoma On A Budget
Owen’s CV is interesting in that unlike many specialists he did a full nine years in practice, after graduating from Cambridge, before embarking on a residency at the RVC. With the qualifications listed above along with his lengthy spell in first opinion practice, he is very well qualified to speak on his topic with first opinion clinicians in mind. The webinar is an excellent comprehensive update on feline lymphoma including full details on the diagnosis and treatment, but with suggestions where compromises are possible to reduce costs.
He begins this veterinary webinar by briefly introducing five different cats all with differing manifestations of lymphoma. These cats lead us onto the first of a list of relevant points throughout the webinar.
POINT 1: Feline lymphoma is a different disease compared to dogs and people.
Cats get extranodal lymphoma most commonly
Cats tend to be sick at the diagnosis
Clinical signs reflect the region of the body affected
The first part, with budgets in mind, deals with diagnosis, further tests after diagnosis and how to approach different presentations. Cytology is an important diagnostic procedure and a lymphoma slide is compared with a reactive lymph node. This may result in a cytological specimen that is equivocal. Three additional tests are discussed-histopathology, PCR for Antigen Receptor Rearrangement, (PARR) and Flow cytometry. These are discussed, but in the context of this webinar only histopathology is selected.
Some more detail is added on two of the initial cases described in the introduction. In one looking for the disease elsewhere was helpful and in the other the most effective diagnostic test was a minimally invasive laparotomy with wedge biopsy of the enlarged lymph node. The interesting discussion on these cats leads to point two:
POINT 2: Where cytology is equivocal or non-diagnostic for cats consider the following, in this order.
Look for diagnosis elsewhere
Therapeutic trial? After considering the quality of the diagnostic test results, consideration of the differential diagnosis and counselling of the client.
Returning to the cat with the enlarged lymph node further tests could be considered. These are FeLV and FIV both with an increased risk for lymphoma, T cell or B cell or WHO classification of histologic subtype. In practice the anatomic site tend to correlate strongly with the type of lymphoma. T cell or B cell is not directly prognostic and only two types of lymphoma are markedly different in their behaviour –these are the low grade diseases.
POINT 3: The grade and anatomic site of the lymphoma are the most important pieces of information to form a prognosis and treatment.
The webinar continues with a full account of the staging system for feline lymphoma from stages I to V, and a list of tests and procedures to enable a ‘full staging’. The prognostic and therapeutic significance for the above is weak, and we are asked ‘why then should we stage feline lymphoma?’ This leads to point 4
POINT 4: Staging rarely affects prognosis or choice of drugs but is useful to.
Detect concurrent disease
Form a baseline for monitoring
To assess whether surgery or radiation could be used
The next section deals with the various presentations of feline lymphoma. These are:
Alimentary lymphomas –low grade GI lymphoma, intermediate/high-grade GI lymphoma and large granular lymphocyte lymphoma
Peripheral Nodal Lymphoma
Low grade ‘Hodgkin like’ lymphomas
CNS involvement in abdominal lymphoma
All are comprehensively summarised with clinical findings, diagnosis, treatment statistics, clinical cases, many illustrations and more-quite an incredible amount of information in the hour!
POINT 5: Disease very commonly occurs in multiple sites in the abdomen and frequently extends to extra-abdominal sites.
The distinction of different anatomic forms of lymphoma is often arbitrary, and many sites may be sub-clinical.
After dealing with all the lymphoma types two more points are
POINT 6: Surgery or radiation therapy are more likely to have a role for the treatment of feline compared to canine lymphoma.
But staging is very important to make sure you don’t have occult disease elsewhere
POINT 7: Response to treatment (complete versus partial) is by far the most important prognostic indicator in intermediate-high grade feline lymphoma at all anatomic sites.
The final part of the webinar lists in detail various treatment protocols including standard, ‘good budget’, cheaper alternatives, even cheaper alternatives, an empirical ‘hands off’ protocol and finally the most palliative approach. These protocols would benefit from downloading for reference. At this point Owen adds his own approach to treatment, with interesting conclusions:
No conclusive benefit of any specific protocol
What matters is whether the cat responds to it
Expense, convenience, ease of administration, number of vet visits, and risk of adverse effects should be important factors in the choice of treatment. Adverse effects are very well summarised for all the chemotherapeutic drugs in the next section.
POINT 8: Both response rates and adverse effects of chemotherapeutic drugs are very different in cats and dogs.
As I mentioned at the beginning of this review, this is as comprehensive as it gets as an update on feline lymphoma. Don’t be mislead by the title. Certainly there is a lot of information on where compromises can be made in diagnosis and treatment but the overall content of this excellent webinar is of a high quality. It will benefit everyone that treats cats, including recent graduates and specialists in training. As I also mentioned a lot of the protocols would benefit from downloading for reference and the statistics are very useful for conversations with owners. A phenomenal amount of work has gone into the webinar-many hours I am quite sure, and I recommend watching it in segments after reflection of each part.