PT - JOURNAL ARTICLE AU - Matthias R. Benz AU - Sarah M. Dry AU - Fritz C. Eilber AU - Martin S. Allen-Auerbach AU - William D. Tap AU - David Elashoff AU - Michael E. Phelps AU - Johannes Czernin TI - Correlation Between Glycolytic Phenotype and Tumor Grade in Soft-Tissue Sarcomas by <sup>18</sup>F-FDG PET AID - 10.2967/jnumed.109.074229 DP - 2010 Aug 01 TA - Journal of Nuclear Medicine PG - 1174--1181 VI - 51 IP - 8 4099 - http://jnm.snmjournals.org/content/51/8/1174.short 4100 - http://jnm.snmjournals.org/content/51/8/1174.full SO - J Nucl Med2010 Aug 01; 51 AB - Tumor glycolytic phenotyping can be accomplished with 18F-FDG PET. Tumor 18F-FDG uptake correlates with tumor grade in several cancers. However, the role of 18F-FDG PET for the grading of soft-tissue sarcomas (STSs) warrants further research. Methods: One hundred two patients (48 men and 54 women; mean age ± SD, 50 ± 17 y) with 12 STS subtypes underwent 18F-FDG PET/CT before treatment. Tumor 18F-FDG uptake, expressed as maximum standardized uptake value (SUVmax), was compared among subtypes and correlated with histopathologic grade. Two frequently used sarcoma grading systems—the 3-tier system of the French Federation of Cancer Centers Sarcoma Group (Fédération Nationale des Centres de Lutte Contre le Cancer [FNCLCC]) and a 2-tier system (low grade vs. high grade)—were used. Results: More than 90% of STSs (93/102) exhibited a strong glycolytic phenotype (SUVmax, 2.7–52.2 g/mL). Tumor SUVmax differed significantly among tumor grades (P &lt; 0.001 for the 3- and 2-tier grading systems). The FNCLCC and 2-tier grading systems predicted tumor grade with similar accuracy (area under the curve, 0.83 and 0.85, respectively; P = 0.35). SUVmax differed significantly among histologic subtypes (P = 0.03) in the entire population but not when high-grade STSs were analyzed separately (P = 0.31). Conclusion: The tumor glycolytic phenotype correlated significantly with histologic grade as determined by both the FNCLCC and 2-tier (high vs. low) grading systems. 18F-FDG PET cannot be used to reliably distinguish among grade 2 and 3 STSs (by FNCLCC) and the various subtypes.