Neoadjuvant pazopanib treatment in high-risk soft tissue sarcoma: a quantitative dynamic 18F-FDG PET/CT study of the German Interdisciplinary Sarcoma Group

  • The outcome of high-risk soft tissue sarcoma (STS) is poor with radical surgery being the only potentially curative modality. Pazopanib is a multikinase inhibitor approved for the treatment of metastatic STS. Herein, in terms of the German Interdisciplinary Sarcoma Group (GISG-04/NOPASS) trial, we evaluate the potential role of kinetic analysis of fludeoxyglucose F-18 (18F-FDG) data derived from the application of dynamic positron emission tomography/computed tomography (PET/CT) in response assessment to pazopanib of STS patients scheduled for surgical resection. Sixteen STS patients treated with pazopanib as neoadjuvant therapy before surgery were enrolled in the analysis. All patients underwent dynamic PET/CT prior to and after pazopanib treatment. Data analysis consisted of visual (qualitative) analysis of the PET/CT scans, semi-quantitative evaluation based on standardized uptake value (SUV) calculations, and quantitative analysis of the dynamic 18F-FDG PET data, based on two-tissue compartment modeling. Resection specimens were histopathologically assessed and the percentage of regression grade was recorded in 14/16 patients. Time to tumor relapse/progression was also calculated. In the follow-up, 12/16 patients (75%) were alive without relapse, while four patients (25%) relapsed, among them one patient died. Median histopathological regression was 20% (mean 26%, range 5–70%). The studied population was dichotomized using a histopathological regression grade of 20% as cut-off. Based on this threshold, 10/14 patients (71%) showed partial remission (PR), while stable disease (SD) was seen in the rest 4 evaluable patients (29%). Semi-quantitative evaluation showed no statistically significant change in the widely used PET parameters, SUVaverage and SUVmax. On the other hand, 18F-FDG kinetic analysis revealed a significant decrease in the perfusion-related parameter K1, which reflects the carrier-mediated transport of 18F-FDG from plasma to tumor. This decrease can be considered as a marker in response to pazopanib in STS and could be due to the anti-angiogenic effect of the therapeutic agent.

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Author:Christos Sachpekidis, Ioannis Karampinis, Jens Jakob, Bernd Kasper, Kai Nowak, Lothar Pilz, Ulrike Attenberger, Timo Gaiser, Hans-Günter Derigs, Matthias Schwarzbach, Peter HohenbergerORCiDGND, Antonia Dimitrakopoulou-Strauss, Ulrich RonellenfitschORCiDGND
Parent Title (English):Cancers
Place of publication:Basel
Document Type:Article
Date of Publication (online):2019/06/08
Date of first Publication:2019/06/08
Publishing Institution:Universitätsbibliothek Johann Christian Senckenberg
Release Date:2020/05/07
Tag:SUV; dynamic 18F-FDG PET/CT; pazopanib; soft tissue sarcoma (STS); two-tissue compartment model
Page Number:13
Institutes:Medizin / Medizin
Dewey Decimal Classification:6 Technik, Medizin, angewandte Wissenschaften / 61 Medizin und Gesundheit / 610 Medizin und Gesundheit
Licence (German):License LogoCreative Commons - Namensnennung 4.0