Is ¹⁸F-FDG PET/CT Useful for the Early Prediction of Histopathologic Response to Neoadjuvant Erlotinib in Patients with Non–Small Cell Lung Cancer?

Abstract

Early prediction of treatment response is of value in avoiding the unnecessary toxicity of ineffective treatment. The objective of this study was to prospectively evaluate the role of integrated 18 F-FDG PET/CT for the early identification of response to neoadjuvant erlotinib, an epidermal growth factor receptor tyrosine kinase inhibitor. Methods: From October 2006 to March 2009, 23 patients with non-small cell lung cancer eligible for surgical resection were evaluated for this study. Patients received preoperative erlotinib (150 mg) once daily for 3 wk. 18 F-FDG PET/CT was performed before and at 1 wk after the administration of erlotinib. Changes in tumor 18 F-FDG uptake during treatment were measured by standardized uptake values and assessed prospectively according to the criteria of the European Organization for Research and Treatment of Cancer. Patients with a decrease in standardized uptake values of 25% or more after 1 wk were classified as "metabolic responders." The metabolic response was compared with the pathologic response, obtained by histopathologic examination of the resected specimen. Results: Following the 18 F-FDG PET/CT criteria of the European Organization for Research and Treatment of Cancer, 6 patients (26%) had a partial response within 1 wk, 16 patients (70%) had stable disease, and 1 patient (4%) had progressive disease. The median percentage of necrosis in the early metabolic responder group was 70% (interquartile range, 30%-91%), and the median percentage of necrosis in the nonresponder group was 40% (interquartile range, 20%-50%; P 5 0.09). The k-agreement between the metabolic and pathologic responders was 0.55 (P 5 0.008). Conclusion: The results of this study suggest that early during the course of epidermal growth factor receptor tyrosine kinase inhibitor therapy, 18 F-FDG PET/CT can predict response to erlotinib treatment in patients with non-small cell lung cancer.

Changes in 18F-Fluorodeoxyglucose and 18F-Fluorodeoxythymidine Positron Emission Tomography Imaging in Patients with Non–Small Cell Lung Cancer Treated with Erlotinib

“…Our results are consistent with and greatly expand on results from several smaller clinical studies of PET imaging in NSCLC patients treated with EGFR inhibitors, although none of these other studies directly compared FDG-and FLT-PET imaging (21)(22)(23)(24)39). For example, Sohn and colleagues found that an FLT-PET scan after 7 days of gefitinib treatment could predict the response to treatment in 28 nonsmokers with advanced adenocarcinoma of the lung (22).…”

Large Decreases in Standardized Uptake Values After Definitive Radiation Are Associated with Better Survival of Patients with Locally Advanced Non–Small Cell Lung Cancer

“…The utility of the SUV for disease staging or its role after neoadjuvant chemotherapy for NSCLC has been described before (3,(24)(25)(26)(27). However, the usefulness of the extent of reduction in SUV after definitive RT, particularly in LNs, for assessing prognosis remains uncertain.…”

Early [18F]Fluorodeoxyglucose Positron Emission Tomography at Two Days of Gefitinib Treatment Predicts Clinical Outcome in Patients with Adenocarcinoma of the Lung

“…18 F]FDG-PET predicted histopathologic response in patients with NSCLC treated with erlotinib as neoadjuvant therapy (31). Metabolic tumor responses were assessed 1 to 8 weeks after the start of erlotinib treatment in these studies.…”