Abstract
This study aims to assess the utility of quantitative dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) parameters in comparison with imaging tumor size for early prediction and evaluation of soft tissue sarcoma response to preoperative chemoradiotherapy. In total, 20 patients with intermediate- to high-grade soft tissue sarcomas received either a phase I trial regimen of sorafenib + chemoradiotherapy (n = 8) or chemoradiotherapy only (n = 12), and underwent DCE-MRI at baseline, after 2 weeks of treatment with sorafenib or after the first chemotherapy cycle, and after therapy completion. MRI tumor size in the longest diameter (LD) was measured according to the RECIST (Response Evaluation Criteria In Solid Tumors) guidelines. Pharmacokinetic analyses of DCE-MRI data were performed using the Shutter-Speed model. After only 2 weeks of treatment with sorafenib or after 1 chemotherapy cycle, Ktrans (rate constant for plasma/interstitium contrast agent transfer) and its percent change were good early predictors of optimal versus suboptimal pathological response with univariate logistic regression C statistics values of 0.90 and 0.80, respectively, whereas RECIST LD percent change was only a fair predictor (C = 0.72). Post-therapy Ktrans, ve (extravascular and extracellular volume fraction), and kep (intravasation rate constant), not RECIST LD, were excellent (C > 0.90) markers of therapy response. Several DCE-MRI parameters before, during, and after therapy showed significant (P < .05) correlations with percent necrosis of resected tumor specimens. In conclusion, absolute values and percent changes of quantitative DCE-MRI parameters provide better early prediction and evaluation of the pathological response of soft tissue sarcoma to preoperative chemoradiotherapy than the conventional measurement of imaging tumor size change.
Highlights
Soft tissue sarcomas are a rare, heterogeneous group of malignancies that can be found in nearly any site in the body, most commonly occurring in the extremities
Consistent with our previously reported findings from the 8 patients with soft tissue sarcoma who were enrolled in the phase I trial of sorafenib ϩ standard chemoradiotherapy [21], this study of a larger cohort of 20 patients shows that changes in tumor functions as measured by quantitative dynamic contrast-enhanced (DCE)-magnetic resonance imaging (MRI) are superior to changes in RECIST-based imaging tumor size measurement for early prediction of pathological response of soft tissue sarcoma to preoperative therapy, suggesting that therapy-induced tumor functional changes precede changes in tumor size
Under the condition of 100% sensitivity for early prediction of optimal response, the specificities are 40% and 60% for V21% RECIST longest diameter (LD) and V21% Ktrans, respectively, indicating less misclassification of suboptimal responders as optimal responders when V21% Ktrans, instead of V21% RECIST LD, is used as the imaging metric for early prediction of response
Summary
Soft tissue sarcomas are a rare, heterogeneous group of malignancies that can be found in nearly any site in the body, most commonly occurring in the extremities. While surgical resection is the mainstay of treatment, large tumors (Ͼ5 cm) with high pathological grade have an unacceptably high rate of metastatic recurrence and subsequent death. Optimal treatment for high-risk sarcomas of the extremities remains undefined, one strategy involves the use of combination preoperative chemotherapy and radiation. The intent of such treatment is to treat micrometastatic disease in hopes of preventing metastatic relapse, to sensitize the tumor to the effects of radiation with chemotherapy to prevent local tumor recurrence, and to potentially downsize the tumor to facilitate surgical resection. A noninvasive imaging method that is useful for prediction and evaluation of soft tissue sarcoma response to preoperative therapy could be a valuable tool to enable personalized treatment
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
