Comparison between a 2-and 3-grade system in predicting metastatic-free survival in extremity soft-tissue sarcoma

Background and Objectives: The purpose of this study was to determine wheth er a histologic grading system consisting of 2 or 3 categories had better d iscrimination for predicting metastasis-free survival in extremity soft-tis sue sarcoma. Methods: One hundred thirty patients with nonmetastatic soft-tissue sarcoma were identified and the histologic grade (3-grade system) for each tumor w as determined. For the 2-grade system, grade was determined by collapsing 3 grades into 2. The Kaplan-Meier method was used to estimate disease free s urvival. Results: By use of a 3-grade system, grade 2 tumors showed a 5.2-fold and g rade 3 tumors a 9-fold increased risk of systemic relapse when compared wit h grade 1 tumors. When grade 2 and 3 tumors were combined, they had a 2.6-f old increased risk of systemic relapse compared with grade 1 tumors. When g rade I and 2 tumors were combined, grade 3 tumors had an 8.4-fold risk of r elapse. After data were controlled for size and depth of tumor, each increa se in grade in the 3-grade system showed a successive 2.3-fold increase in risk of systemic relapse. Conclusions: A 3-grade system may be more appropriate for predicting system ic relapse than 2 grades. A prospective study is required to confirm this. (C) 1999 Wiley-Liss, Inc.