Salvage versus amputation- What it takes
One of the most vexing problems that patients and their parents have is what to expect in the management of malignant bone tumors. After years of experience in dealing with patients with these challenging conditions, the most common questions are if chemotherapy or radiation is going to be necessary (somehow the acceptance of the necessity of surgery is never in question) and then whether the limb can be saved (not necessarily in that order). Once those questions are answered, the natural questions on the course of management begin to unfold. We present here a short synopsis of the typical steps involved in the management of a patient with osteosarcoma to help answer some of these questions.
Figure 1. The patient undergoes chemotherapy following a biopsy for about 11 weeks. If there is good response, the serum alkaline phosphatase will normalize. On x-rays there is typically increased calcification. The MRI may actually show a larger tumor if it is necrotic (dead) or more importantly the blood flow to the tumor reduces. If there are reduced metastatic deposits or increased calcification of existing lesions, this indicates a good response to chemotherapy. The bone scan can show reduced blood flow or necrosis of the tumor.
Figure 2. At surgery the biopsy tract is excised. The tumor is removed (about 90 minutes) and all the margins are assessed intra-operatively for contamination. One has to decide if an allograft or prosthesis will be used to fill the defect. With prosthetics, the return to function is almost immediate.
Figure 3. Meanwhile, the specimen is preserved in formalin and de-calcified over about a week to make it soft enough to cut (it is virtually impossible to cut bone in a delicate manner). It is first split to examine the margins for contamination. A section of this is then sliced to get a geographically representative specimen. This in turn is painstakingly evaluated for necrosis.
Figure 4. The managing team then meets again (typically in a tumor board) to discuss if the results of histology tally with the findings radiologically and to recommend further treatment. This whole cycle takes about 3 weeks whence the patient resumes the rest of the 35-week course of chemotherapy.