Palliative Chemotherapy for Liposarcoma in Dogs
Dear OncoLink "Ask The Experts,"
My Irish Wolfhound was diagnosed a little over a year ago (at age 3) with a very large, very invasive liposarcoma in the left lumbar region, effacing the musculature in this region, eating into several lumbar vertebrae and extending into the abdominal region. She received palliative radiation a year ago and was given 3-6 months to live. The radiation completely alleviated her extreme pain and shrunk the tumor considerably. Today, she is doing extremely well, living an active, pain-free life. I have moved to another state since her radiation and recently took her to the local veterinary teaching hospital for a check-up and evaluation with an oncologist. She is not a candidate for further palliative radiation due to the lysis in her spine. The oncology department says the only protocol option available to her is chemotherapy with adriamycin. However, they have told me that there is nothing in the veterinary medical literature indicating any records of any dog with liposarcoma having been treated palliatively with chemotherapy. I am wondering if this is accurate information and, if not precisely accurate, whether you have knowledge of the outcome of chemotherapy on canine liposarcoma with regard to its palliative effects?
Thank you very much for your help.
Lili Duda, VMD, Section Editor of the OncoLink Veterinary Oncology Menu, responds:
This is a very good question. While it is technically true that there are no reports of the specific drug doxorubicin (Adriamycin) to treat the specific tumor type liposarcoma, what is true is that doxorubicin is quite commonly used to palliate soft tissue sarcomas in dogs and cats. Doxorubicin has documented activity against a wide variety of soft tissue sarcomas in dogs, cats, and humans, and is considered a first-line choice for this general tumor type, both in the palliative, adjuvant, and neo-adjuvant settings. Liposarcomas are relatively uncommon soft-tissue sarcomas in dogs, and arise from the fatty connective tissues. They tend to be intermediate to high grade tumors, although the treatment aim is still controlling the primary tumor, as this is usually the clinical problem rather than metastatic spread. As a very general rule-of-thumb, the more rapidly growing the tumor, the more likely it is to have a good initial response to chemotherapy, although it is also more likely to become resistant within a few months. The general protocol when using chemotherapy in a palliative fashion is to give two "cycles" of chemotherapy (in the case of doxorubicin it can be given every 2 to 3 weeks) and then evaluate for response--if the drug is having the desired effect (e.g. decrease in pain or compression), then it can be continued for a total of about 6-8 cycles before the maximum tolerable dose is attained.