The present study assessed the predictive value of (99m)Tc-3(poly-(ethylene glycol), PEG) 4-arginine-glycine-aspartic ((99m)Tc-3P-RGD2) single photon emission computed tomography (SPECT) for the early identification of response to antiangiogenic treatment with bevacizumab in patients with advanced non-small cell lung cancer (NSCLC). Patients with advanced NSCLC treated with bevacizumab were prospectively studied with (99m)Tc-3P-RGD2 SPECT before and after 2 weeks from start of treatment. The tumor response was evaluated with RECIST criteria and related to observed change in the tumor to non-tumor (T/N) ratio for the largest known lesion. Receiver operating characteristic (ROC) curve analysis was used to determine T/N ratio changes with regard to predicting response to bevacizumab therapy. Change in T/N ratio was also related to progression-free survival (PFS) and overall survival (OS). Twenty-six patients were included, and 23 were finally assessable for metabolic response evaluation with (99m)Tc-3P-RGD2 SPECT. The cut-off value of T/N ratio change defined by ROC analysis was 24.4%. The sensitivity, specificity, and negative predictive value of (99m)Tc-3P-RGD2 SPECT for predicting tumor response were 81.8%, 91.7%, and 84.6%, respectively. Using the cut-off value defined by ROC analysis on (99m)Tc-3P-RGD2 SPECT, metabolic non-progressive disease patients (mNP) showed prolonged PFS (5.6 months versus 3.4 months; P < 0.001) and OS (17.1 months versus 8.6 months; P < 0.001) than metabolic progressive disease patients (mP). (99m)Tc-3P-RGD2 SPECT scan is a promising test to predict tumor response in patients with advanced non-small cell lung cancer early in the course of bevacizumab therapy.
Keywords: 99mTc-3P-RGD2; SPECT; bevacizumab; non-small cell lung cancer; response.