Multidisciplinary approach to osteosarcoma.

Osteosarcoma is a malignant bone tumor composed of mesenchymal cells producing osteoid and immature bone. Osteosarcoma is the most frequent primary malignant bone tumor, if we excluded myeloma, a haematologic disease. The incidence of osteosarcoma is 2-3/million/year, but is higher in adolescence, in which the annual incidence peaks at 8-11/million/year at 15-19 years of age. Local pain, followed by localized swelling and limitation of joint movement, are the typical signs and symptoms. Correct diagnosis can be achieved through a correct approach to the disease and the combination of clinical and radiographic aspects. The final step to confirm the diagnosis is the biopsy. Computer Tomography of the chest and Positron-Emission Tomography are mandatory to complete the staging, which is performed according the Musculoskeletal Tumor Society staging system. A multidisciplinary approach is needed both to get to a correct diagnosis (orthopaedic surgeon, radiologist and histopathologist) and to perform definitive treatment. Multidisciplinary approach should be performed in reference centers able to provide access to the full spectrum of care and where orthopaedic surgeon, oncologist, histopathologist, radiologist and radiotherapist can cooperate. The management of osteosarcoma is based primarily on neo-adjuvant and adjuvant chemotherapy and surgical resection; radiotherapy is not effective as osteosarcomas are relatively radioresistant. Prognostic factors include metastases at presentation, histologic response to induction chemotherapy, the site of the primary tumor (with axial lesions having an inferior outcome), serum lactate dehydrogenase and alkaline phosphatase levels.