PET imaging of patients with non-small cell lung cancer employing an EGF receptor targeting drug as tracer

BACKGROUND: We have previously developed (11)C-erlotinib as a new positron emission tomography (PET) tracer and shown that it accumulates in epidermal growth factor receptor (EGFR)-positive lung cancer xenografts in mice. Here, we present a study in patients with non-small cell lung cancer (NSCLC) investigating the feasibility of (11)C-erlotinib PET as a potential method for the identification of lung tumours accumulating erlotinib. METHODS: Thirteen patients with NSCLC destined for erlotinib treatment were examined by contrast-enhanced computed tomography (CT), (11)C-erlotinib PET/low-dose CT and (18)F-fluoro-2-deoxy-D-glucose ((18)F-FDG) PET/low-dose CT before start of the erlotinib treatment. After 12 weeks treatment, they were examined by (18)F-FDG PET/contrast-enhanced CT for the assessment of clinical response. RESULTS: Of the 13 patients included, 4 accumulated (11)C-erlotinib in one or more of their lung tumours or lymph-node metastases. Moreover, (11)C-erlotinib PET/CT identified lesions that were not visible on (18)F-FDG PET/CT. Of the four patients with accumulation of (11)C-erlotinib, one died before follow-up, whereas the other three showed a positive response to erlotinib treatment. Three of the nine patients with no accumulation died before follow-up, four showed progressive disease while two had stable disease after 12 weeks of treatment. CONCLUSION: Our data show a potential for (11)C-erlotinib PET/CT for visualizing NSCLC lung tumours, including lymph nodes not identified by (18)F-FDG PET/CT. Large clinical studies are now needed to explore to which extent pre-treatment (11)C-erlotinib PET/CT can predict erlotinib treatment response.