PT  - JOURNAL ARTICLE
AU  - Praus Christine
AU  - Ralph Bundschuh
AU  - Ken Herrmann
AU  - Robert Rosenberg
AU  - Jens Stollfuss
AU  - Karen Becker
AU  - Sybille Ziegler
AU  - Helmut Friess
AU  - Markus Schwaiger
AU  - Bernd-Joachim Krause
TI  - Comparison of different SUV-based methods for response prediction to neoadjuvant radiochemotherapy in locally advanced rectal cancer by FDG-PET/CT
DP  - 2008 May 01
TA  - Journal of Nuclear Medicine
PG  - 383P--383P
VI  - 49
IP  - supplement 1
4099  - http://jnm.snmjournals.org/content/49/supplement_1/383P.4.short
4100  - http://jnm.snmjournals.org/content/49/supplement_1/383P.4.full
SO  - J Nucl Med2008 May 01; 49
AB  - 1617 Objectives: The aim of this study was to compare different SUV-based analysis methods of F-18-FDG PET/CT data for prediction of histopathological response (HPR) to neoadjuvant radiochemotherapy (RCTx) in patients with rectal cancer. Methods: 28 patients with uT3 rectal cancer underwent serial FDG-PET/CT scans at baseline, 14 days after initiation and after completion of RCTx. FDG uptake was assessed by calculating the mean SUV within different geometries: standard 2D region of interest (ROI, diameter 1.5 cm) and 3D volumes of interest (VOIs) with a fixed diameter as well as threshold based VOIs. Changes between SUVs at the defined time points were calculated and analysed for their potential to predict HPR to RCTx (ROC analysis). Results: Histopathology classified eight of 28 patients as non-responders and 20 patients as responders to RCTx. ROC analysis of the standard 2D ROI technique revealed areas under the curve (AUCs) of 0.649 and 0.702 for the early and late time point. Corresponding AUCs for 3D VOI techniques resulted in AUCs ranging from 0.694 - 0.722 (early time point) and 0.762 - 0.786 (later time point), respectively. AUCs of isocontours with a fixed or organ-defined cut-off showed values of 0.667 - 0.684 (early time point) and 0.595 - 0.667 (later time point). Conclusions: Our pilot study demonstrates that 3D based approaches for assessing SUV values result in better AUC values for prediction of HPR to neoadjuvant RCTx in patients with rectal cancer.