Early Response Assessment to Targeted Therapy Using 3′-deoxy-3′[(18)F]-Fluorothymidine (18F-FLT) PET/CT in Lung Cancer

Although 2-deoxy-2-[18F]-fluoro-D-glucose positron emission tomography/computed tomography (18F-FDG PET/CT) is a sensitive nuclear medicine modality, specificity for characterizing lung cancer is limited. Tumor proliferation and early response to molecularly targeted therapy could be visualized using 3′-deoxy-3′[(18)F]-fluorothymidine (18F-FLT) PET/CT. The superiority of 18F-FLT PET/CT over 18F-FDG PET/CT in early therapeutic monitoring has been well described in patients after chemotherapy, radiotherapy, and/or chemo/radiotherapy. In thispilot study, we explorethe use of 18F-FLT PET/CT as an early response evaluation modality in patients with lung cancerand provide specific case studies of patients with small cell lung cancer and non-small cell lung cancer who received novel targeted therapies. Early response for c-MET inhibitor was observed in four weeks and for MDM2 inhibitor in nine days.