¹⁸F-FDG PET/CT for Monitoring Treatment Responses to the Epidermal Growth Factor Receptor Inhibitor Erlotinib

Abstract

Response rates of unselected non–small cell lung cancer (NSCLC) patients to the epidermal growth factor receptor inhibitor erlotinib are low and range from 10% to 20%. Early response assessments are needed to avoid costs and side effects of inefficient treatments. Here we determined whether early changes in tumor uptake of 18F-FDG can predict progression-free and overall survival in NSCLC patients who are treated with erlotinib. Methods Twenty-two patients (6 men, 16 women; mean age ± SD, 64 ± 13 y) with stage III or stage IV NSCLC who received erlotinib treatment were enrolled prospectively. 18F-FDG PET/CT was performed before the initiation of treatment (n = 22), after 2 wk (n = 22), and after 78 ± 21 d (n = 11). Tumor maximum standardized uptake values were measured for a maximum of 5 lesions for each patient. Tumor responses were classified using modified PET Response Criteria in Solid Tumors (use of maximum standardized uptake values). Median overall survival by Kaplan–Meier analysis was compared between groups using a log-rank test. Results The overall median time to progression was 52 d (95% confidence interval, 47–57 d). The overall median survival time was 131 d (95% confidence interval, 0–351 d). Patients with progressive metabolic disease on early follow-up PET showed a significantly shorter time to progression (47 vs. 119 d; P < 0.001) and overall survival (87 vs. 828 d; P = 0.01) than patients classified as having stable metabolic disease or partial or complete metabolic response. Conclusion These data suggest that 18F-FDG PET/CT performed early after the start of erlotinib treatment can help to identify patients who benefit from this targeted therapy.

Timing of Metabolic Response Monitoring During Erlotinib Treatment in Non–Small Cell Lung Cancer

“…Metabolic imaging of NSCLC and several other tumor types has been shown to be valuable in response assessment in the setting of targeted therapy (10)(11)(12)(13)(14). 18 F-FDG PET/CT provides information about tumor metabolic activity, which may be useful for monitoring molecular changes associated with the treatment response (15,16).…”

Harnessing Preclinical Molecular Imaging to Inform Advances in Personalized Cancer Medicine

“…Attenuated 18 F-FDG consumption was observed within hours of the combination treatment and could predict therapeutic outcome. Although clinical studies are beyond the scope of this review, they largely mirror what has been identified in preclinical studies: rapid changes in 18 F-FDG uptake-in some cases as early as 24-48 h after treatment-can predict a therapeutic response to oncogene-targeted therapy (23,24). Thus, 18 F-FDG PET may be particularly valuable for quickly evaluating whether a new therapy or therapeutic strategy that either directly or indirectly targets glucose uptake can elicit an important functional tumor response.…”

From diagnosis to therapy in lung cancer: management of CT detected pulmonary nodules, a summary of the 2015 Chinese-German Lung Cancer Expert Panel

“…Early FDG PET-CT after the start of erlotinib treatment identified patients who benefited from this targeted therapy (36). Thirty-four patients with untreated stage IV NSCLC were evaluated in this phase II trial.…”