Early [18F]fluorodeoxyglucose positron emission tomography at two days of gefitinib treatment predicts clinical outcome in patients with adenocarcinoma of the lung.
OBJECTIVE
Positron emission tomography (PET) with [(18)F]fluorodeoxyglucose (FDG) is increasingly used in early assessment of tumor response after chemotherapy. We investigated whether a change in [(18)F]FDG uptake at 2 days of gefitinib treatment predicts outcome in patients with lung adenocarcinoma.


METHODS
Twenty patients were enrolled. [(18)F]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 (R(2) = 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).


CONCLUSIONS
Early assessment of [(18)F]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.
Department of Respiratory Medicine, Allergy and Rheumatic Diseases, Osaka University Graduate School of Medicine, Suita, Osaka, Japan.
Ryo
R
Takahashi
Haruhiko
H
Hirata
Isao
I
Tachibana
Eku
E
Shimosegawa
Atsuo
A
Inoue
Izumi
I
Nagatomo
Yoshito
Y
Takeda
Hiroshi
H
Kida
Sho
S
Goya
Takashi
T
Kijima
Mitsuhiro
M
Yoshida
Toru
T
Kumagai
Atsushi
A
Kumanogoh
Meinoshin
M
Okumura
Jun
J
Hatazawa
Ichiro
I
Kawase
D000230:Adenocarcinoma / Q000000981:diagnostic imaging* / Q000188:drug therapy / Q000401:mortality; D000368:Aged; D000369:Aged, 80 and over; D000970:Antineoplastic Agents / Q000627:therapeutic use; D018196:Carcinoma, Adenosquamous / Q000000981:diagnostic imaging* / Q000188:drug therapy / Q000401:mortality; D066246:ErbB Receptors / Q000235:genetics; D005260:Female; D019788:Fluorodeoxyglucose F18; D000077156:Gefitinib; D006801:Humans; D008175:Lung Neoplasms / Q000000981:diagnostic imaging* / Q000188:drug therapy / Q000401:mortality; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D009154:Mutation / Q000235:genetics; D049268:Positron-Emission Tomography; D011379:Prognosis; D011799:Quinazolines / Q000627:therapeutic use*; D019275:Radiopharmaceuticals; D015996:Survival Rate; D014057:Tomography, X-Ray Computed
D000970:Antineoplastic Agents; D011799:Quinazolines; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18; C512478:EGFR protein, human; D066246:ErbB Receptors; D000077156:Gefitinib