Dear OncoLink "Ask the Experts,"
My 7 year old Australian Shepherd has been diagnosed with a liposarcoma on his upper left thigh. The vet could not guarantee good surgical margins with removal of the limb and portion of the pelvic area. Despite the absence of any spread of the disease to other portions of the body, I am reluctant to go ahead with the amputation because of a 20 lb. weight loss over a 1 1/2 year period. The doctor does not give a good prognosis. I am very confused about my decision and have heard that a liposarcoma in a dog is very rare. I would appreciate any information or advice that you may have on my situation.
Lili Duda, VMD, Editor of the OncoLink Veterinary Oncology Section, responds:
Liposarcomas are indeed relatively uncommon tumors in dogs. These cancers arise from the fatty connective tissues of the body. However, they behave similar to other medium to high-grade soft tissue sarcomas. These tumors can be very locally invasive and also have the potential to metastasize in some animals.
Wide surgical margins are required to control the tumor locally, which can be difficult to obtain when the tumor occurs in the upper thigh. Sometimes an MRI or CT scan is performed to evaluate the extent of the tumor and to avoid surgery in those cases where amputation and hemipelvectomy would clearly not provide adequate surgical margins. An abdominal ultrasound might also be useful to evaluate sublumbar lymph nodes as well as internal organs.
Another treatment option might be high energy radiation therapy alone or radiation followed by surgery to remove the residual tumor. Chemotherapy plays an uncertain role in these tumors. By itself, chemotherapy is strictly palliative. It may offer some benefit if combined with surgery and/or radiation therapy in both controlling local tumor and delaying metastasis, but this remains unproven. The weight loss appears unexplained at this time and should probably be evaluated to be sure your dog does not have another problem that needs to be addressed.
If you or your veterinarian have not already done so, please consult a qualified veterinary oncologist to further explore the treatment options for your pet.