Dr. Timothy Fan answers this reader query about controlling cancer pain.
Dr. Fan welcomes oncology questions from veterinarians and veterinary technicians.
I have a 6-year old female spayed Doberman pinscher in which appendicular osteosarcoma was recently diagnosed. We are currently treating her with carprofen, tramadol, and gabapentin. I also started her on an intravenous treatment regimen every 28 days with pamidronate. Have you seen much success in pain management with pamidronate? How many treatments do dogs need to receive before you notice any progress? I would also like to know if there are any other helpful options for this condition.
A. Appendicular osteosarcoma is a neoplastic condition characterized by focal malignant osteolysis. Pain associated with osteosarcoma is the direct result of physical bone destruction and associated inflammation that stimulates peripheral pain fibers (nociceptors). Treatments that minimize or reverse the rate and degree of pathologic bone destruction can provide analgesia.
Dr. Timothy M. Fan
Pamidronate is a second-generation bisphosphonate that reduces malignant osteolysis by inducing apoptosis of osteoclasts. The use of pamidronate in dogs to manage osteosarcoma-associated pain has been reported in combination with conventional oral analgesics, such as what you are administering to your dog, with about 30% of treated patients achieving durable pain alleviation in excess of four months.1,2 Given its favorable toxicity profile, dogs with appendicular osteosarcoma can be treated with intravenous pamidronate monthly for the entirety of their disease process without cumulative adverse effects.
Although potent intravenous bisphosphonates appear to have a role in managing malignant bone pain, the use of ionizing radiation therapy remains the first-line and most effective treatment modality for controlling pain secondary to focal skeletal osteolysis in dogs. So I would recommend that you add ionizing radiation therapy to improve pain control in your dog, if possible.
1. Fan TM, de Lorimier LP, Charney SC, et al. Evaluation of intravenous pamidronate administration in 33 cancer-bearing dogs with primary or secondary bone involvement. J Vet Intern Med 2005;19(1):74-80.
2. Fan TM, de Lorimier LP, O'Dell-Anderson K, et al. Single-agent pamidronate for palliative therapy of canine appendicular osteosarcoma bone pain. J Vet Intern Med 2007;21(3):431-439.
Timothy M. Fan, DVM, PhD, DACVIM (internal medicine, oncology)
Department of Veterinary Clinical Medicine
College of Veterinary Medicine
University of Illinois
Urbana, IL 61802