PRINCIPLES OF STAGING OF SOFT-TISSUE SARCOMAS

The TNM staging system is a modus for diagnosis and treatment in which T is the extent of the tumor involvement, N is lymph node involvement , and M is the metastases; this system is supplemented with a histolog ic malignancy grade. Staging systems identify specific prognostic fact ors with which to predict clinical outcome. Staging systems are useful for assigning treatment priorities, determining the role of adjuvant therapies, and evaluating clinical investigations. Unfortunately, no u niversally accepted staging system for soft-tissue sarcomas exists. Th is is related to the relatively low incidence of sarcomas, the unique and unpredictable behavior of sarcomas, significant disagreement regar ding histogenesis and grading, and lack of consensus regarding the val ue of various prognostic factors. In adults, the two most commonly use d staging systems are those developed by the American Joint Committee on Cancer and by Enneking. In children, the Intergroup Rhabdomyosarcom a Study and the International Union Against Cancer have described the systems most commonly used. These systems for soft-tissue sarcomas rel y on an ability to accurately determine both the local and distant ext ent of disease. Advances in the field of computed tomography and magne tic resonance imaging have made this possible. It is likely that a sta ging system based upon a more sophisticated understanding of the basic biology of sarcomas will become available.