[Tc]3PRGD for integrin receptor imaging of esophageal cancer: a comparative study with [F]FDG PET/CT.

ObjectivesThis study was designed to investigate the efficacy of (99m)technetium-three polyethylene glycol spacers-arginine-glycine-aspartic acid ([Tc-99m]3PRGD(2)) in the evaluation of patients with esophageal cancer.MethodsTwenty-nine patients with a suspected esophageal lesion and for whom definite pathological diagnosis was finally obtained were recruited. Whole-body planar scanning and chest single-photon-emission computed tomography/computed tomography (SPECT/CT) were performed at 30 and 40min, respectively, after intravenous injection of 11.1MBq/kg of [Tc-99m]3PRGD(2). 2-Deoxy-2-[F-18] fluoro-d-glucose ([F-18]FDG) positron-emission tomography/computed tomography (PET/CT) was performed in 1week. The tumor-to-background ratio (T/B) and the maximum standard uptake value (SUVmax) were calculated for semi-quantitative and quantitative analyses. Integrin (v3) was analyzed through immunohistochemistry.ResultsThe T/B, SUVmax and expression of integrin (v3) in malignant lesions were higher than those in benign lesions (t=3.691, P=0.001; t=8.271, P=0.000; t=3.632, P=0.001, respectively). There was a significant correlation between T/B and SUVmax in esophageal lesions (r=0.660, P=0.000). The expression of integrin (v3) was correlated with [Tc-99m]3PRGD(2) uptake (r=0.782, P=0.000). In visual analysis, the sensitivity and accuracy of the whole-body planar RGD scan were lower than those of the chest SPECT/CT RGD scan and the [F-18]FDG PET/CT scan (x(2)=6.769, P=0.022). The sensitivity, specificity and accuracy of the chest SPECT/CT RGD scan were similar to those of the [F-18] FDG PET/CT scan. In semi-quantitative analysis, the sensitivity, specificity and accuracy of chest SPECT/CT RGD from the receiver operating characteristic (ROC) analysis were 87%, 100% and 94%, respectively [cutoff=3.1 of T/B, area under the curve (AUC)=0.957]. Thirteen patients (30 lymph nodes) and 16 patients (105 lymph nodes) were suspected to have lymph node metastases based on the RGD and FDG scans, respectively.ConclusionThis prospective study demonstrated that [Tc-99m]3PRGD(2) imaging is valuable for the diagnosis and staging of esophageal cancer. It may be less sensitive than [F-18]FDG imaging for detecting metastatic lesions in small lymph nodes. The T/B value was correlated with the expression of integrin (v3).NIH ClinicalTrials.govNCT 02744729.