Data from Early [&lt;sup&gt;18&lt;/sup&gt;F]Fluorodeoxyglucose Positron Emission Tomography at Two Days of Gefitinib Treatment Predicts Clinical Outcome in Patients with Adenocarcinoma of the Lung

Jun Hatazawa,Mitsuhiro Yoshida,Ryo Takahashi,Isao Tachibana,Ichiro Kawase,Hiroshi Kida,Atsushi Kumanogoh,Sho Goya,Izumi Nagatomo,Eku Shimosegawa,Meinoshin Okumura,Haruhiko Hirata,Atsuo Inoue,Takashi Kijima,Yoshito Takeda,Toru Kumagai

doi:10.1158/1078-0432.c.6520854

Abstract

<div>AbstractPurpose: Positron emission tomography (PET) with [18F]fluorodeoxyglucose (FDG) is increasingly used in early assessment of tumor response after chemotherapy. We investigated whether a change in [18F]FDG uptake at 2 days of gefitinib treatment predicts outcome in patients with lung adenocarcinoma.Experimental Design: Twenty patients were enrolled. [18F]FDG-PET/computed tomographic (CT) scan was carried out before and 2 days after gefitinib treatment. Maximum standardized uptake values (SUV) were measured, and post-gefitinib percentage changes in SUV were calculated. Early metabolic response (SUV decline < −25%) was compared with morphologic response evaluated by CT scan and with progression-free survival (PFS).Results: At 2 days of gefitinib treatment, 10 patients (50%) showed metabolic response, 8 had metabolic stable disease, and 2 had progressive metabolic disease. Percentage changes of SUV at 2 days were correlated with those of tumor size in CT at 1 month (R2 = 0.496; P = 0.0008). EGFR gene was assessable in 15 patients, and of 12 patients with EGFR mutations, 8 showed metabolic response at 2 days and 6 showed morphologic response at 1 month. None of 3 patients with wild-type EGFR showed metabolic or morphologic response. Metabolic response at 2 days was not statistically associated with PFS (P = 0.095), but when a cutoff value of −20% in SUV decline was used, metabolic responders had longer PFS (P < 0.0001).Conclusion: Early assessment of [18F]FDG tumor uptake with PET at 2 days of gefitinib treatment could be useful to predict clinical outcome earlier than conventional CT evaluation in patients with lung adenocarcinoma. Clin Cancer Res; 18(1); 220–8. ©2011 AACR.</div>

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