The majority of dogs are able to walk unassisted within 12 to 24 hours of limb amputation. Dogs should be encouraged to walk and exercise to improve the speed of recovery. The surgical wound should be checked twice daily for signs of infection or breakdown (called dehiscence). These signs include redness, swelling, watery to purulent discharge, and pain.
After limb-sparing surgery, the limb should be lightly bandaged and the bandages should be changed frequently for 2 to 3 weeks. Exercise is started immediately after surgery but should be restricted to leashed walks for the first 4 weeks. Exercise is important in preventing toe contracture and minimizing swelling of the foot and toes, both of which can occur as a consequence of exercising certain muscles and blood vessels during surgery.
For dogs with appendicular osteosarcoma, the median survival time for following palliative treatment is 90 to 175 days, with 45-50% of dogs alive at 6 months and 15-20% alive at 12 months after diagnosis. However, median survival times of approximately 300 days have been reported following treatment with palliative radiation therapy and chemotherapy. In contrast, the median survival time following curative-intent treatment is 235 to 366 days, with up to 33-65% of dogs alive at 12 months and 16-28% alive at 2 years. Alkaline phosphatase is an enzyme analyzed in the preoperative blood tests, which has been shown to be associated with the duration of survival following surgery and chemotherapy. The median survival time for dogs with a normal alkaline phosphatase level is approximately 12.5 months compared to 5.5 months if alkaline phosphatase is increased at the time of diagnosis. Other factors that may influence prognosis in dogs with appendicular osteosarcoma include tumor size and location and histologic grade.
For dogs with appendicular chondrosarcoma, the survival time following limb amputation alone (i.e., no chemotherapy)ranges from a median survival time of 540 days to a mean survival time of 2618 days (median was not reached because less than 50% of dogs died as a result of their tumor). Grading of chondrosarcoma is important to determine prognosis because the median survival times for dogs with grade I, II and III chondrosarcomas are significantly different at 6 years, 2.7 years, and 0.9 years, respectively. Metastasis is reported in approximately 30% of dogs with chondrosarcoma, but this usually occurs late in the course of the disease and chemotherapy does not decrease the metastatic rate or improve survival time in dogs with chondrosarcoma.
Appendicular fibrosarcoma and hemangiosarcoma are rare and the prognosis is difficult to determine. However, metastasis is relatively common in dogs with hemangiosarcoma and, for this reason; survival times are generally poor with less than 10% of dogs alive at 12 months after limb amputation.
In contrast to dogs, cats with appendicular osteosarcoma have a low metastatic rate (less than 10%) and the median survival time following amputation alone is over 350 days (and up to 4 years).
The prognosis for axial bone tumors is dependent on tumor type and location. In general, osteosarcoma of the scapula and pelvis has a similar prognosis to appendicular osteosarcoma following either palliative or curative-intent treatment. The median survival times reported for osteosarcoma of the head (i.e., mandible, maxilla, and skull) are poor with most less than 12 months. The most common reason for this poor survival time is local recurrence of the tumor and not metastasis. However, the importance of aggressive surgical treatment is highlighted by the fact that most dogs are cured, with a median survival time greater than 1,500 days, if the tumor is completely resected.
Multilobular osteochondrosarcoma (multilobular tumor of bone) is a tumor of the axial skeleton and commonly affects the skull bones. The prognosis for dogs with multilobular osteochondrosarcoma depends on whether the tumor has been completely removed and on the histologic grade. Local tumor recurrence and metastasis are more common following incomplete tumor resection. The rate of local tumor recurrence is 30%, 47%, and 78% for grade I, II, and III multilobular osteochondrosarcoma, respectively. The metastatic rate of multilobular osteochondrosarcoma is also dependent on histologic grade, with metastasis, usually to the lungs, occurring in 30%, 60%, and 78% of grade I, II, and III tumors, respectively. The overall median survival time for dogs with multilobular osteochondrosarcoma is 669 to 797 days, with a median survival time greater than 897 days for dogs with grade I tumors, 520 days for dogs with grade II tumors, and 405 days for dogs with grade III tumors. Importantly, multilobular osteochondrosarcoma is a slow growing tumor and prolonged survival after diagnosis of metastatic disease is common (median, 239 days).
Rib osteosarcoma is an aggressive tumor. Metastasis is diagnosed at the time of death in 100% of dogs with osteosarcoma, 67% of dogs with hemangiosarcoma, and up to 100% of dogs with fibrosarcoma. Factors, which influence prognosis in dogs with rib tumors, include tumor type and completeness of surgical resection. Local recurrence of a rib tumor is over 5 times more likely if the rib tumor was not completely resected. The median survival time for dogs with rib osteosarcoma is 90 days with surgery alone and 240-290 days if surgery is combined with chemotherapy. In comparison, the median survival time for dogs with rib chondrosarcoma is 1,080 to greater than 3,750 days with surgery alone.
The prognosis for dogs with vertebral tumors is usually poor. Regardless of tumor type, the median survival time for malignant vertebral tumors is 135 days. Tumor type, tumor location, and postoperative treatment (i.e., chemotherapy or radiation therapy) do not improve survival time. However, using guidelines employed by human neurosurgeons, there are anecdotal reports of prolonged survival following aggressive surgical resection, with or without postoperative radiation therapy.