Chemotherapy for Treatment of Lymphoma in Dogs and Cats
Lymphoma, a cancer of the white blood cells, is the most common cancer of dogs and cats. It usually is diagnosed as solid masses either in peripheral lymph nodes (dogs) or gastrointestinal tract (cats). The treatment of choice for this disease is chemotherapy, usually a multiple-drug regimen, and although we cannot cure this disease, up to 90% of dogs and 65% of cats go into remission.
With complete remission, all signs of cancer are gone. The typical length of a treatment is 6 months, and if the patient is in remission at 6 months the chemotherapy can be discontinued. The pet is then monitored monthly for signs of the cancer returning. When the cancer returns, chemotherapy can be restarted, using either the same or a different medicine protocol. The length of the second remission is usually shorter than the first remission.
Without treatment, patients with lymphoma usually only live for 4 to 6 weeks. With appropriate treatment, however, dogs have a median survival time of 1 year with 25% of patients living for 2 years. Cats that are treated have a median survival time of 7 months, however cats with low grade lymphoma in the gastrointestinal tract typically have a good prognosis and survival times of 2 years.
There are currently no specialists in Veterinary Oncology in Hong Kong. However, the Internal Medicine Service at VSH has many patients who are undergoing chemotherapy or who have successfully completed their chemotherapy protocols. Fortunately, there is a large degree of overlap in the specialty training taken on by Internal Medicine Specialists and Oncologists. Dr. Josh, with the close assistance of a board-certified Veterinary Oncologist in San Diego, helps to evaluate and treat not only a patient's cancer, but also any underlying conditions that may complicate the disease. VSH Hong Kong has a specially ventilated room and specific protective materials for chemotherapy drugs, keeping our staff and patients safe at all times. In the photos seen here, Specialty Nurse Christy is preparing chemotherapy drugs using very special equipment, protective clothing, and a ventilation hood.
One patient currently undergoing lymphoma treatment is Gi Gi. Gi Gi is a 9 year old female spayed Corgi who came to the emergency service at VSH for increased breathing rate and effort. Several weeks prior to coming to VSH she was seen by her family veterinarian for a swelling under her neck, which initially got better with antibiotics. At her next recheck, it was noted that all of her lymph nodes were enlarged. Over the next week she stopped eating and was having diarrhea. Blood tests showed an elevated white blood cell count along with a low platelet count. A sample from one of her lymph nodes was consistent with high grade lymphoma. We discussed all the options with her owner and decided to start her on chemotherapy after consultation with a board certified oncologist.
Gi Gi is 5 weeks into her chemotherapy protocol and has gone into remission and is currently doing well at home. As part of the chemotherapy she comes in once a week to the clinic for a physical examination, blood work and based on those results the decision whether or not to give chemotherapy is made.