Relationship Between Clinicopathological Characteristics and PET/CT Uptake in Esophageal Squamous Cell Carcinoma: [18F]Alfatide versus [18F]FDG.

To assess a novel radiotracer aluminum [18F]fluoride-1,4,7-triazacyclononane-triacetic acid-pegylated dimeric RGD ([18F]ALF-NOTA-PRGD2, denoted as [18F]Alfatide) for positron emission tomography (PET)/X-ray computed tomography (CT) and explore the relationships between clinicopathological characteristics and maximum standard uptake values in primary (SUVP) and metastatic lymph nodes (SUVLN) of patients with esophageal squamous cell carcinoma (ESCC), as verified by pathologic examination and compared with those obtained with 2-deoxy-2-[18F]fluoro-D-glucose ([18F]DG) PET. We prospectively enrolled patients with newly diagnosed ESCC who agreed to undergo [18F]Alfatide PET/CT or [18F]FDG PET/CT scans before surgery at Shandong Cancer Hospital from May 2011 to July 2017. SUVs and the pathological tumor-node-metastasis (pTNM) stages of primary tumors and metastatic lymph nodes (LNs) were measured and confirmed pathologically. Immunohistochemical (IHC) staining for integrin αvβ3 was performed on tumor samples (both primary tumors and metastatic LNs) collected from nine patients. Of 61 patients who underwent PET/CT scans, 46 then underwent curative surgery and were included in our analysis (n = 21 for [18F]Alfatide PET/CT and n = 25 for [18F]FDG PET/CT). No significant differences in the SUVP on [18F]Alfatide PET/CT or [18F]FDG PET/CT were observed among the cohorts according to gender, pathological stage, T stage, status of LNs, and differentiation (all P > 0.05). The SUVLN differed significantly between the pathological stages and status of LNs both on [18F]Alfatide PET/CT (P = 0.03, 0.003) and [18F]FDG PET/CT (P = 0.001. < 0.001), but not according to gender (P = 0.128, 0.129), T stage (P = 0.791, 0.727), or tumor differentiation (P = 0.049, 0.053). Significant positive correlations were observed between the SUVLN on [18F]Alfatide PET/CT and [18F]FDG PET/CT, and pathological stage (r = 0.52, P = 0.016; r = 0.503, P = 0.01), LN status (r = 0.73, P < 0.001; r = 0.649, P < 0.001), and differentiation (r = 0.509, P < 0.019; r = 0.459, P = 0.021) were observed. No significant differences were found between the relationships of SUVP with SUVLN, length, age, gender, pathological stage, T stage, status of LN, or differentiation, or of SUVLN with length, age, gender, or T stage both on [18F]Alfatide PET/CT and [18F]FDG PET/CT (all P > 0.05). The quantitated expression levels of αvβ3 in primary tumors and metastatic LNs were 1.67 ± 1.12 and 3.42 ± 2.93, respectively (P = 0.031). Our results suggest that SUVLN is influenced by pathological stage, LN status, and differentiation. SUVLN may therefore serve as a new parameter for risk stratification of with ESCC patients. Moreover, [18F]Alfatide PET can provide complementary molecular information about ESCC metastasis.