LAUSR

PurposeTo explore the relationship between metabolic uptake of the 18F-ALF-NOTA-PRGD2 (18F-RGD) tracer on positron emission tomography/computerized tomography (PET/CT) and the antiangiogenic effect of apatinib in patients with solid malignancies.Materials and patientsPatients with measurable lesions scheduled for second- or third-line single-agent therapy with apatinib were eligible for this prospective clinical trial. All patients underwent 18F-RGD PET/CT examination before the start of treatment. Standardized uptake values (SUVs) of contoured tumor lesions were computed and compared using independent sample t-tests or the Mann–Whitney U test. Receiver-operating characteristic (ROC) curve analysis was used to determine accuracy in predicting response. Survival curves were compared using the Kaplan–Meier method.ResultsOf 38 patients who consented to study participation, 25 patients with 42 measurable lesions met the criteria for inclusion in this response assessment analysis. The median follow-up time was 3 months (range, 1–10 months), and the median progression-free survival (PFS) was 3 months (95% confidence interval, 1.04–4.96). The SUVpeak and SUVmean were significantly higher in responding tumors than in non-responding tumors (4.98 ± 2.34 vs 3.59 ± 1.44, p = 0.048; 3.71 ± 1.15 vs 2.95 ± 0.49, P = 0.036). SUVmax did not differ between responding tumors and non-responding tumors (6.58 ± 3.33 vs 4.74 ± 1.83, P = 0.078). An exploratory ROC curve analysis indicated that SUVmean [area under the ROC curve (AUC) = 0.700] was a better parameter than SUVpeak (AUC = 0.689) for predicting response. Using a threshold value of 3.82, high SUVmean at baseline was associated with improved PFS (5.0 vs. 3.4 months, log-rank P = 0.036).Conclusion18F-RGD uptake on PET/CT imaging pretreatment may predict the response to antiangiogenic therapy, with higher 18F-RGD uptake in tumors predicting a better response to apatinib therapy.