RT Journal Article SR Electronic T1 Timing of Metabolic Response Monitoring During Erlotinib Treatment in Non–Small Cell Lung Cancer JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP 1081 OP 1086 DO 10.2967/jnumed.113.130674 VO 55 IS 7 A1 Matthijs H. van Gool A1 Tjeerd S. Aukema A1 Eva E. Schaake A1 Herman Rijna A1 Renato A. Valdés Olmos A1 Renée van Pel A1 Sjaak A. Burgers A1 Harm van Tinteren A1 Houke M. Klomp YR 2014 UL http://jnm.snmjournals.org/content/55/7/1081.abstract AB The purpose of this study was to prospectively evaluate the timing of metabolic response monitoring with 18F-FDG PET of (neoadjuvant) erlotinib treatment in patients with early-stage non–small cell lung cancer. Methods: This study was designed as an open-label phase II trial performed in 4 hospitals in The Netherlands. Patients received preoperative erlotinib (150 mg) once daily for 3 wk. Response evaluation was performed after 4–7 d and at 3 wk with 18F-FDG PET/CT scans. Tumor 18F-FDG uptake and changes were measured as standardized uptake values (SUVs). The metabolic response was classified on the basis of European Organization for Research and Treatment of Cancer criteria (>25% decrease in the maximum SUV) and was compared with histopathologic regression as observed in the resection specimen. Results: From December 2006 to November 2010, 60 patients with non–small cell lung cancer eligible for surgical resection were enrolled in this study. For 43 patients (18 men and 25 women), baseline 18F-FDG PET/CT scans as well as both monitoring scans and histopathologic response monitoring were available. A partial metabolic response on 18F-FDG PET/CT scans was observed for 10 patients (23%) after 1 wk and for 14 patients (33%) after 3 wk. Histopathologic examination revealed regression (necrosis of >50%) in 11 patients (26%). In these patients, the maximum SUV decreased by a mean of 17% within 1 wk and a mean of 31% at 3 wk. Seven patients were identified as responders within 1 wk. Conclusion: Response monitoring with 18F-FDG PET/CT within 1 wk after the start of erlotinib treatment identified approximately 64% of histopathologic responders on the basis of European Organization for Research and Treatment of Cancer criteria.