Evaluation of the response for gefitinib in patients with non-small cell lung cancer (NSCLC) using FDG-PET scan

Abstract

9703 Background: Fluorine-18 fluorodeoxyglucose positron emission tomography (FDG-PET) scan is reported as useful and accurate nuclear medicine method for diagnosis of malignancy/benign, staging, metastasis and recurrence in primary lung cancer. Gefitinib (Iressa) is an orally active, selective EGFR-tyrosine kinase inhibitor that blocks signal transduction pathways implicated in proliferation and survival of cancer cells. Phase II trial to evaluate objective tumor response rate and safety of ZD1839 was operated worldwide in patients with previously treated NSCLC. In this study, we aimed to evaluate the usefulness of FDG-PET scan for the response of gefitinib in NSCLC. Method: Fourteen patients of recurrent or chemotherapy refractory NCSLC administered 250 mg/day of gefitinib were analyzed. Twelve patients treated with gefitinib evaluated the response using conventional CT scan were compared with FDG-PET scan at a time. Two patients diagnosed for BAC (bronchioloalveolar carcinoma) could not be analyzed because of no FDG uptake before treatment. The response of FDG-PET scan was analyzed with standard uptake value (SUV) change and visualized evaluation by 2 pulmonary oncologists. Results: Four PRs, 8 SDs and 2 PD were evaluated with CT scan. Eight of 12 (66.7%) patients had the same result with both methods. Four SDs (33.3%) evaluated with CT scan had a result of PR in FDG-PET scan. Two of these patients were reevaluated to PR with CT scan in 4–8 weeks later. Conclusions: These results suggest that the response of FDG-PET scan was earlier than that of CT scan in patients treated with gefitinib. FDG-PET scan might be used in routine practice to evaluate the chemotherapeutic response of molecular target agents including gefitinib in primary lung cancer. Large prospective study with precise design is necessary. No significant financial relationships to disclose.