Sampling modality influences the predictive value of grading in adult soft tissue extremity sarcomas

Abstract

Context: Histologic grade is one of the best predictors of outcome in adult soft tissue sarcomas. Current grading systems were validated on resection specimens; however, there has been a trend toward the use of biopsies to diagnosis these tumors. Objectives.-To determine whether the grade of an extremity soft tissue sarcoma determined on tissue obtained by either core needle biopsy or incisional biopsy is predictive of metastasis- or disease-free survival, and whether either sampling modality is superior. Design: One hundred three core needle biopsies and 107 incisional biopsies of nonmetastatic spindle cell sarcomas of the extremities were retrieved from the archives. All cases had a minimum 2-year follow-up. Patient data and outcome and tumor characteristics were recorded. Tumors were reviewed and evaluated using the French Federation of Cancer Centers Sarcoma Group grading system. Kaplan-Meier survival curves were generated to correlate tumor grade with metastasis- and diseasefree survival for both groups. Results: Patient and tumor characteristics were similar between groups except that more tumors were grade 3 and superficial in the incisional biopsy group. Grade determined on core needle biopsy was not predictive of either metastasis-free survival (P=.59) or disease-free survival (P =.50). In contrast, grade determined on incisional biopsy was predictive of both metastasis-free survival (P