| Popis: |
New developments in staging have given greater importance to the imaging of soft-tissue sarcomas since the time of the last articles on soft-tissue tumors in the Instructional Course Lectures9,19 or even more recent reviews37. Whereas previous articles have focused on the diagnosis, treatment, and molecular biology of benign19 and malignant9 soft-tissue tumors, the current article will present a new modification of the staging system that has been proposed by the American Joint Committee on Cancer38. Imaging techniques and unique characteristics of soft-tissue tumors will be discussed in order to demonstrate how they are related to the new criteria for staging. The main purpose of staging a tumor is to determine a patient's prognosis and to help to direct treatment. Malignant tumors have been described as having a life cycle. Therefore, staging identifies specific time-points in a tumor's life cycle (Fig. 1). Staging is usually done at the time that a malignant tumor is diagnosed, but restaging may be performed if the disease progresses and the patient becomes a candidate for various treatment protocols or other clinical research trials46. Pathological criteria, such as the histological grade, amount of necrosis, and size of the tumor as determined at the time of excision, are commonly used for the staging of carcinomas of the skin, bowel, prostate, cervix, and so on. However, in the case of soft-tissue sarcomas, the initiation of treatment such as chemotherapy or radiation before the tumor is excised may alter such factors as the size of the tumor and the amount of necrosis, thus reducing the accuracy of pathological staging that is based on the resected tumor. Therefore, staging based on the pathological characteristics of the resected tumor has given way to staging based on both clinical factors (such … |
