Early predictive and prognostic value of 18F-fluorodeoxyglucose positron emission tomography-CT for response assessment in non-small cell lung cancer treated with epidermal growth factor receptor tyrosine kinase inhibitor / 中华放射学杂志

ABSTRACT

Objective To evaluate whether an early change in 18F-fluorodeoxyglucose (18F-FDG) uptake can predict tumor response to epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) and prognosis in patients with non-small cell lung cancer (NSCLC). Methods From August 2009 to April 2015, 22 patients with NSCLC who were eligible to EGFR-TKI treatment were enrolled. PET-CT scan was performed before (baseline) and 1 month after EGFR-TKI administration. Up to 5 hottest single tumor lesions (no more than 2 per organ) were considered to be target lesions. Maximum standardized uptake values (SUVmax) were measured, and post-treatment percentage changes in SUVmax (ΔSUV%) were calculated. PET responses were classified using PET response criteria in solid tumors (PERCIST). Then conventional CT scan was performed every 2 months for follow-up. Kappa statistic was used to compare agreement between the RERCIST recommendations-based therapeutic response evaluation and those based on RECIST1.1 criteria. Fisher exact test was used to compare the probability of disease progression in the early metabolic response and non-response groups. Predictive accuracy of ΔSUV% with respect to response or non-progression at CT scan was evaluated by ROC analysis. Progression-free survival (PFS) was determined by Kaplan-Meier survival analysis, and between-group comparison was performed by log-rank test. Results After 1 month of EGFR-TKI treatment, 12 patients (55%) showed partial metabolic response (PMR), 6 (27%) had stable metabolic disease (SMD), and 4 (18%) had progressive metabolic disease (PMD). There was a moderate agreement(Kappa=0.506,P<0.05) between PET response at 1 month based on PERCIST recommendations and CT response at 3 months according to RECIST 1.1. Non-progression was significantly more frequent in patients with an early PMR (χ2=11.941, P=0.005). Progression had been confirmed later during therapy in all patients with PMD . By using ROC analysis, the area under the curve for prediction of response was 0.906 (95% CI, 0.766—1.000; P=0.002), corresponding to a sensitivity of 88.9% and specificity of 84.6% at a cut-off of 40.36% in ΔSUV%. Using a cut-off value of 25.84% in ΔSUV%, highΔSUV% group (ΔSUV% ≥ 25.84%) had significantly longer PFS than low ΔSUV% group (ΔSUV%<25.84%). Conclusion Early assessment of PET-CT at 1 month of EGFR-TKI treatment could be useful to predict tumor response and clinical outcome in patients with NSCLC.