Early [18F]Fluorodeoxyglucose Positron Emission Tomography at 2 days of Gefitinib Treatment Predicts Clinical Outcome in Patients with Adenocarcinoma of the Lung
Menée sur 20 patients atteints d'un adénocarcinome pulmonaire, cette étude évalue l'intérêt d'une tomographie par émission de positrons à l'aide de 18-FDG réalisée deux jours après un traitement au gefinitib pour prédire la réponse thérapeutique
Purpose: Positron emission tomography (PET) with [18F]fluorodeoxyglucose (FDG) is increasingly used in early assessment of tumor response after chemotherapy. We investigated if 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 tomography (CT) scan was performed before and 2 days after gefitinib treatment. Maximum standardized uptake values (SUVs) were measured, and post-gefitinib percent 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 were metabolic stable disease, and 2 had progressive metabolic disease. Percent 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 of -20% in SUV decline was used, metabolic responders had longer PFS (P < 0.0001). Conclusions: 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.
Clinical Cancer Research , résumé, 2011