Usefulness of 18FDG-positron emission tomography (FDG-PET) for early prediction of erlotinib (Eb) treatment outcome in non-small cell lung cancer (NSCLC) patients: Results of a pilot study

7568 Background: FDG-PET could be useful for early evaluation of tumor response to tyrosine kinase inhibitors (TKI). Glucose metabolic activity seems to closely reflect response to epidermal growth factor receptor (EGFR) TKI in vivo and in vitro (Su H et al, Clin Cancer Res 2006;12:5659–67). Thus, we attempted to assess the clinical value of FDG-PET for early prediction of tumor response to Eb an EGFR-TKI. Methods: Pts with NSCLC stage IV in progression after at least one line of chemotherapy and PS 0–1 were treated with Eb (150 mg orally once daily). FDG-PET was performed on days 0 and 2, after administration of 3 daily doses. FDG uptake was evaluated as the maximum standardized uptake value in the tumor (SUVmax). SUVmax was divided by SUV of the background region (liver) to produce the tumor:nontumor ratio (TNT). FDG-PET responses were evaluated by quantitative changes on TNT and classified according to the EORTC PET study group. PET response were compared with radiographic tumor response (RECIST criter...