Today an older, large breed dog presented for occasional limping for the past month. The limping had not been getting progressively worse but had not improved either. When I was feeling the bones of the dog, she was extremely painful over the area of her front leg, just above the paw. X-rays were diagnostic for osteosarcoma. Osteosarcoma is a bone tumor that we see mostly in large breed dogs. It usually occurs on the bones "away from the elbow and towards the knee". A bone biopsy could also have been done to provide definitive diagnosis but due to location and appearance of bony changes on the x-ray, we were able to diagnose osteocarcoma in the patient.
Dogs with osteosarcoma, or OSA, may be noticed by owners as a subtle lameness after exercising or rough playing with other dogs. The owners may notice a small swelling over the bone as well. Metastasis to the lungs occurs in 10% of the cases. Therapy for OSA involves amputation of the affected limb. Amputation provides good control of the bone tumor but does not prolong survival time. A median survival time of 19 weeks is seen after amputation due to metastasis. Chemotherapy in combination with amputation has been shown to increase survival times if spread of the tumor has not occurred, but is not effective in treating metastasis of the primary tumor.
Our client elected to try intense pain management to help improve the quality of life of their dog, but she is aware that the prognosis is very poor for long term survival.
Any limping in your dog or cat that does not improve within 24 hours warrants a visit to your veterinarian.
