title: Comparison between a 2- and 3-grade system in predicting metastatic-free survival in extremity soft-tissue sarcoma.
abstract: OBJECTIVE
  The purpose of this study was to determine whether a histologic grading system consisting of 2 or 3 categories had better discrimination for predicting metastasis-free survival in extremity soft-tissue sarcoma.
  
  
  METHODS
  One hundred thirty patients with nonmetastatic soft-tissue sarcoma were identified and the histologic grade (3-grade system) for each tumor was 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 survival.
  
  
  RESULTS
  By use of a 3-grade system, grade 2 tumors showed a 5.2-fold and grade 3 tumors a 9-fold increased risk of systemic relapse when compared with grade 1 tumors. When grade 2 and 3 tumors were combined, they had a 2.6-fold increased risk of systemic relapse compared with grade 1 tumors. When grade 1 and 2 tumors were combined, grade 3 tumors had an 8.4-fold risk of relapse. After data were controlled for size and depth of tumor, each increase 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 systemic relapse than 2 grades. A prospective study is required to confirm this.
authors.affiliation: Department of Pathology and Laboratory Medicine, Mount Sinai Hospital, Toronto, Ontario, Canada.
authors.forename: R A
authors.initials: RA
authors.lastname: Kandel
authors.forename: R S
authors.initials: RS
authors.lastname: Bell
authors.forename: J S
authors.initials: JS
authors.lastname: Wunder
authors.forename: B
authors.initials: B
authors.lastname: O'Sullivan
authors.forename: C N
authors.initials: CN
authors.lastname: Catton
authors.forename: L M
authors.initials: LM
authors.lastname: White
authors.forename: A M
authors.initials: AM
authors.lastname: Davis
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D003627:Data Interpretation, Statistical; D018572:Disease-Free Survival; D005121:Extremities; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging / Q000379:methods*; D012008:Recurrence; D012306:Risk; D012509:Sarcoma / Q000473:pathology*; D012983:Soft Tissue Neoplasms / Q000473:pathology*; D016019:Survival Analysis