Luis Javier Pina MD, PhD, Presenter: Nothing to Disclose

Amaja Garcia-Lallana, Abstract Co-Author: Nothing to Disclose

Valentina Boni, Abstract Co-Author: Nothing to Disclose

Jose Manuel Lopez Vega, Abstract Co-Author: Nothing to Disclose

Arlette Elizalde, Abstract Co-Author: Nothing to Disclose

Jesus GarcÍa-Foncillas, Abstract Co-Author: Research support, F. Hoffmann-La Roche Ltd

Maria J. Garcia-Velloso MD, PhD, Abstract Co-Author: Nothing to Disclose

To investigate the relationship between changes in vascularity and metabolic activity measured by dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and 18F-FLT-positron emission tomography (PET) in breast tumors undergoing bevacizumab administration

PET and MRI examinations were performed in 47 patients with II-III clinical stage breast cancer before and after Bevacizumav administration (15 mg/kg) prospectively enrolled in a clinical trial (2009-011037-27). DCE-MRI parameters included Ktrans (forward transfer constant from vascular space to the tumor), Kep (reverse rate constant from tumor to the vascular space), and Ve (extravascular volume fraction). Spearman rank-order correlations were assessed between SUVmax values assessed by FLT-PET and MRI parameters, and measures were compared between patients before and after bevacizumab administration by Wilcoxon no-parametric paired test.

A correlation between FLT-PET, Krans and Kep was found (r=0.61 and r=0.56, p<0.001). A significant decrease after Bevacizumab was showed in tumor vascularity and proliferation assessed by DCE-MRI and FLT-PET, respectively. The median decrease in Ktrans and Kep were 39% (22-59) and 35% (35-47). Moreover, the changes in Ktrans were correlated with changes in tumor proliferation (r=0.316, p=0.03).

Bevacizumab determines a marked decrease in tumor vascularity and proliferation rates as shown by changes in DCE-MRI and 18F-FLT PET parameters. More proliferative tumors showed higher Ktrans and Kep values. Further investigations are necessary to assess the value of combined PET and MRI for evaluating tumor pharmacodynamics in response to Bevacizumab.

DCE-MRI can be used to detect changes in tumor vascularity after the administration of antiangiogenic drugs, and can be correlated with the metabolic activity measured by PET

Pina, L, Garcia-Lallana, A, Boni, V, Lopez Vega, J, Elizalde, A, GarcÍa-Foncillas, J, Garcia-Velloso, M, Correlation between DCE-MRI and 18F-FLT-PET in Patients with II-III Clinical Stage Breast Cancer before and after BEVACIZUMAB Administration.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11016166.html