Lymphoma in Dogs and Cats – Which Chemotherapy Protocol?

Presenter – Shasta Lynch BVSc(hons) MANZCVS(SAM) MRCVS, Oncologist at Davies Veterinary Specialists

Treating lymphoma can be a minefield, with multiple drug protocols to be considered, and convincing owners that dreaded word ‘chemotherapy’ is the right choice for them and their pet. Last week’s veterinary webinar led by Shasta Lynch from Davies Veterinary Specialists covering lymphoma in cats and dogs helped bring clarity to the approach we should take to each individual case and the best treatment options available.

Considering the best treatment protocol for each individual case was the main aim of this veterinary webinar and Shasta explained that this is affected by the location of the tumour, the immonuphenotype and the tumour grade as well as the owner’s financial situation and the temperament of the patient.

The most common presentation of lymphoma in the dog is a high grade B-cell lymphoma and the first line treatment for this would be the CHOP protocol (vincristine, cyclophosphamide, doxorubicin and prednisolone). This protocol is associated with the longest survival times of 10-12 months and a median remission time of 6-12months with 20-25% of dogs still alive at 2 years. Shasta understood why some vets may not be comfortable using doxorubicin as part of the protocol because of its potential side effects and safety concerns over preparing and administering the product. She advised that it is possible to order doxorubicin prepared at the patients dose in a needle closed syringe which is the safest approach. However if vets in general practice are still concerned they can administer the prednisolone, vincrisitne and cyclophosphamide in practice and refer to a specialist centre on the ‘doxorubicin’ days.

If the use of doxorubicin is not appropriate perhaps for financial reasons or if the animal has underlying cardiac issues then the COP (cyclophosphamide, vincristine and prednisolone) protocol is perfectly acceptable and gives a median remission time of 6 months.

If the temperament of a patient makes intravenous administration of drugs difficult then oral treatment with lomustine and prednisolone can be offered. According to published data this gives a median remission time of 6 weeks although in Shasta’s clinical experience it tends to give a longer remission time of 2-4 months. Liver enzymes need to be monitored when using lomustine as it can cause liver toxicity and these cases should always be under concomitant treatment with SAMe and silybin. This protocol is also the protocol of choice for cases of cutaneous epitheliotrophic lymphoma.

Shasta gave really practical and relevant advice on how to administer many of these chemotherapy agents as safely as possible. The use of frusemide alongside cylophosphamide and at what neutrophil levels chemotherapy should be delayed were just some of the many tips offered by this veterinary webinar.

Treatment of lymphoma in cats was also included although there is much less published data available and greater variation in anatomic location and histological type, with treatment options being much less predictable. With lymphoma in cats and dogs being encountered relatively frequently in practice, this is a veterinary webinar which should not be missed and provides a safe course through that minefield of treatment options.

The Stethoscope (MRCVS)

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One response to “Lymphoma in Dogs and Cats – Which Chemotherapy Protocol?”

  1. Lisa says:

    Good article that shows the dog owner there is different options. For this reason I think using a vet oncologist is the way to go. With so many different options and different factors to consider, it is unrealistic for dog owners to expect a primary vet who has so much to know on so many topics,to have the knowledge in cancer that a specialist has.

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