The complexity of prognostication in musculoskeletal sarcomas. An analysis of four illustrative entities

Sammanfattning: Although malignant musculoskeletal tumors are rare, they encompass numerous entities with a wide morphological, clinical and prognostic spectrum. Sarcoma surgery is particularly demanding. Treatment must take into account the lesionís inherent biologic behavior, anatomic location and individual patient factors. Meaningful prognostic studies require large series of specific entities with long-term follow-up. The highly specialized and centralized diagnosis and treatment of sarcomas at Sahlgrenska University Hospital in G teborg, Sweden have made such studies possible. The purpose of this study was to identify significant prognostic factors with respect to specific types of sarcoma and sarcomas in general. To this end, four entities, including two soft tissue sarcomas and two sarcomas of bone, were analyzed. The long-term biologic behavior of extraskeletal myxoid chondrosarcoma (117 cases), its broad morphologic spectrum, and a largely unrecognized cellular variant are described. Only clinical factors, including older patient age, proximal tumor location, and larger tumor size, were found to be independent adverse prognostic factors. The 5-, 10-, and 15-year survivals were 90%, 70% and 60%, respectively. In the series of synovial sarcoma (121 cases), low and high-risk groups with overall disease free survivals of 88% and 18%, respectively, were identified. Features of the high-risk group included patient age >25 years, tumor size >5 cm., and poorly differentiated areas of tumor. Patients with synovial sarcoma had 5-, 10-, and 15 year-survivals of 60%, 50% and 40%, respectively. Patients with sacral and spinal chordoma (39 cases) had 5-, 10-, 15- and 20-year-survivals of 80%, 64%, 52% and 52%, respectively. The overall local recurrence rate was 44%. Adverse prognostic factors were larger tumor size, tumor necrosis and proliferative index (Ki67 >5%). Patients with chondrosarcoma of the pelvis, sacrum and spine (69 cases) had 5-, 10-, 15- and 20-year-survivals of 72%, 67%, 63% and 60%, respectively. The overall local recurrence rate was 27%. Adverse prognostic factors were older patient age, sacral tumor location and tumor grade. All four studies illustrated the prognostic importance of adequate surgical margins and center-based diagnosis and treatment for sarcomas.Conclusions: (1) Histologic grade is prognostically highly significant in some sarcomas, such as synovial sarcoma and chondrosarcoma of bone, whereas it is of no significance in others, such as extraskeletal myxoid chondrosarcoma and chordoma. (2) Prognostic factors must be determined for each specific type of sarcoma. (3) Specialized, center-based diagnosis and treatment of sarcomas contribute to markedly improved outcome. (4) Modern, aggressive surgical techniques, particularly those dealing with sarcomas of the axial skeleton, significantly improve local control and survival and decrease functional sequelae.