Soft-Tissue Sarcomas: Assessment of MRI Features Correlating with Histologic Grade  and Patient Outcome.

Crombé A, Marcellin PJ, Buy X, Stoeckle E, Brouste V, Italiano A, Le Loarer F, Kind M.

Radiology, Jun 2019

doi: 10.1148/radiol.2019181659. Epub


Background Managing soft-tissue sarcoma (STS) relies on histologic grade, which is the strongest prognostic factor and a routine assessment at biopsy. However, underestimation of histologic grade may occur because of tumor heterogeneity. Purpose To identify MRI features that are associated with high-grade STS (grade III) and to determine the relationship between MRI features and patient survival. Materials and Methods In this retrospective single-center study, patients (age ≥16 years) were included if they presented with STS diagnosed between 2008 and 2015, had a baseline contrast material-enhanced MRI study, had a pathologic grade assessed on the whole surgical specimen, and had no history of neoadjuvant treatment. Visceral sarcomas, well-differentiated liposarcomas, and angiosarcomas were excluded. Images were evaluated for size, heterogeneity, architecture, margins, and surrounding tissue at T2-weighted, T1-weighted precontrast, and T1-weighted postcontrast MRI. χ2 tests, Fisher tests, and multivariable binary logistic regression were performed to identify features associated with a final grade of III. The associations between combinations of these features and overall survival and metastasis-free survival were investigated with Kaplan-Meier curves and multivariable Cox models. Results A total of 130 patients were included (53 women [mean age ± standard deviation, 60.7 years ± 19.2]); 72 of the 130 (55.4%) STSs were grade III. At multivariable analysis, three MRI features were associated with grade III STS: peritumoral enhancement (odds ratio [OR], 3.4; P = .003), presence of an area compatible with necrosis (OR, 2.4; P = .03), and heterogeneous signal intensities greater than or equal to 50% at T2-weighted imaging (OR, 2.3; P = .04). The presence of at least two of these three features was an independent predictor of metastasis-free survival (hazard ratio, 4.5; P = .01) and overall survival (hazard ratio, 4.2; P = .04). Conclusion MRI features including necrosis, heterogeneity, and peritumoral enhancement of soft-tissue sarcomas were associated with grade III tumors, metastasis-free survival, and overall survival.

© RSNA, 2019.