Alexander Sterzik, Presenter: Nothing to Disclose

Michael Staehler MD, Abstract Co-Author: Nothing to Disclose

Jozefina Casuscelli, Abstract Co-Author: Nothing to Disclose

Martina Karpitschka MD, Abstract Co-Author: Nothing to Disclose

Florian Schwarz MD, Abstract Co-Author: Nothing to Disclose

Maximilian F. Reiser MD, Abstract Co-Author: Nothing to Disclose

Anno Graser MD, Abstract Co-Author: Speakers Bureau, Siemens AG Speakers Bureau, Bracco Group Speakers Bureau, Pfizer Inc Consultant, Bayer AG Grant, Bayer AG

To evaluate the role of dynamic contrast-enhanced computertomography (DCE-CT, perfusion CT) as a potential biomarker in predicting response to antiangiogenic therapy with multikinase inhibitors (MKI) in patients with metastatic renal cell carcinoma (mRCC). ).

48 mRCC patients were prospectively enrolled of which 38 were included in the current study. CT perfusion imaging of representative metastatic lesions was performed before and 8 weeks after start of treatment with Sunitinib (n=28) or Pazopanib (n=10). The DCE-CT protocol included a targeted dynamic acquisition starting 4 - 8 s after injection of 50 ml of contrast media at 6 ml/s using a 4D spiral mode technique (10 cm z-axis coverage, scan duration 44sec, 100 kVp (abdomen), 80 kVp (chest), 100 mAs) on a dual source scanner (Siemens Somatom Definition Flash). Blood flow (BF), blood volume (BV) and permeability-surface area product (PS) were calculated for the entire tumor volume. DCE-CT results were correlated with Response Evaluation Criteria in Solid Tumors response (RECIST) and with progression-free interval (PFI) using Spearman rank correlation, Wilcoxon test, Mann-Whitney U test and Kaplan-Meier statistics.

Responders (n=14) - defined by their best overall response according to RECIST – showed significantly higher baseline values of BF and BV as well as a significantly higher reduction of BF/BF parameters after 8 weeks of AAT than those with stable disease (n = 21) or progressive disease (n=4), (all p-values <0.05). A definition of >50% reduction of BF and BV after 8 weeks of antiangiogenic therapy as a cut-off value was identified to optimally discriminate patients with favorable outcome (median PFI of 10 months) from those with early progression (median PFI of 4 months) and enabled with a sensitivity and specificity of 75%, respectively 90% identification of poor responders with a PFI of < 7 months.

In patients with mRCC relative changes of tumor BF and BV assessed with CTP after 8 weeks of antiangiogenic MKI-treatment may allow prognostic estimations of early therapy failure.

Perfusion-CT predicts reponse to MKI-therapy in patients with mRCC allowing identification of poor responders with early therapy failure and therefore might help to optimize oncologic treatment in this tumor entity.

Sterzik, A, Staehler, M, Casuscelli, J, Karpitschka, M, Schwarz, F, Reiser, M, Graser, A, Perfusion-CT as a Potential Predictor for Response to Antiangiogenic Therapy with Multikinase Inhibitors in Patients with Metastatic Renal Cell Cancer: Preliminary Results of a Pilot Study.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14011408.html