TY - JOUR T1 - Quantitative Analysis of Response to Treatment with Erlotinib in Advanced Non–Small Cell Lung Cancer Using <sup>18</sup>F-FDG and 3′-Deoxy-3′-<sup>18</sup>F-Fluorothymidine PET JF - Journal of Nuclear Medicine JO - J Nucl Med SP - 1871 LP - 1877 DO - 10.2967/jnumed.111.094458 VL - 52 IS - 12 AU - Deniz Kahraman AU - Matthias Scheffler AU - Thomas Zander AU - Lucia Nogova AU - Adriaan A. Lammertsma AU - Ronald Boellaard AU - Bernd Neumaier AU - Roland T. Ullrich AU - Arne Holstein AU - Markus Dietlein AU - Jürgen Wolf AU - Carsten Kobe Y1 - 2011/12/01 UR - http://jnm.snmjournals.org/content/52/12/1871.abstract N2 - The purpose of this study was to evaluate the relevance for the prediction of clinical benefit of first-line treatment with erlotinib using different quantitative parameters for PET with both 18F-FDG and 3′-deoxy-3′-18F-fluorothymidine (18F-FLT) in patients with advanced non–small cell lung cancer. Methods: Data were used from a prospective trial involving patients with untreated stage IV non–small cell lung cancer. 18F-FDG PET and 18F-FLT PET were performed before and 1 (early) and 6 (late) weeks after erlotinib treatment. Several quantitative standardized uptake values (SUVs) using different definitions of volumes of interest with varying isocontours (maximum SUV [SUVmax], 2-dimensional peak SUV [SUV2Dpeak], 3-dimensional [3D] peak SUV [SUV3Dpeak], 3D isocontour at 50% of the maximum pixel value [SUV50], 3D isocontour at 50% adapted for background [SUVA50], 3D isocontour at 41% of the maximum pixel value adapted for background [SUVA41], 3D isocontour at 70% of the maximum pixel value [SUV70], 3D isocontour at 70% adapted for background [SUVA70], and relative SUV threshold level [SUVRTL]) and metabolically active volume measurements were obtained in the hottest single tumor lesion and in the sum of up to 5 lesions per scan in 30 patients. Metabolic response was defined as a minimum reduction of 30% in each of the different SUVs and as a minimum reduction of 45% in metabolically active volume. Progression-free survival (PFS) was compared between patients with and without metabolic response measured with each of the different parameters, using Kaplan–Meier statistics and a log-rank test. Results: Patients with a metabolic response on early 18F-FDG PET and 18F-FLT PET in the hottest single tumor lesion as well as in the sum of up to 5 lesions per scan had a significantly longer PFS, regardless of the method used to calculate SUV. However, the highest significance was obtained for SUVmax, SUV50, SUVA50, and SUVA41. Patients with a metabolic response measured by SUVmax and SUV3Dpeak on late 18F-FDG PET in the hottest single tumor lesion had a significantly longer PFS. Furthermore, Kaplan–Meier analyses showed a strong association between PFS and response seen by metabolically active volume, measured either in early 18F-FLT or in late 18F-FDG. Conclusion: Early 18F-FDG PET and 18F-FLT PET can predict PFS regardless of the method used for SUV calculation. However, SUVmax, SUV50, SUVA50, and SUVA41 measured with 18F-FDG might be the best robust SUV to use for early response prediction. Metabolically active volume measurement in early 18F-FLT PET and late 18F-FDG PET may have an additional predictive value in monitoring response in patients with advanced non–small cell lung cancer treated with erlotinib. ER -