Comparison of [18F]FDG and [68 Ga]pentixafor PET/CT in Nasopharyngeal Carcinoma

Purpose This study aimed to explore the feasibility of [(68) Ga]pentixafor positron emission tomography/computed tomography (PET/CT) in patients with nasopharyngeal carcinoma (NPC).<br /> Procedures This prospective study included patients with NPC who underwent [(68) Ga]pentixafor PET/CT and 2-[F-18]fuoro-2-deoxy-D-glucose ([F-18]FDG) PET/CT within one week between November 2022 and March 2023. The [(68) Ga]pentixafor and [F-18]FDG uptakes in primary and metastatic lesions were measured and compared.<br /> Results Twenty-five participants (21 patients for initial stage and four patients for recurrence detection) were enrolled in our study. The participants underwent [F-18]FDG PET/CT and [(68) Ga]pentixafor PET/CT. [(68) Ga]pentixafor PET/CT had the same detection rate as [F-18]FDG for primary tumor (96% vs. 96%). The [(68) Ga]pentixafor maximum standard uptake value (SUVmax) and target-to-background ratio (TBR) of primary tumors were lower than those of [F-18]FDG (SUVmax: 8.13 +/- 2.78 vs. 14.25 +/- 6.45; P < 0.01; TBR: 5.17 +/- 2.14 vs. 9.81 +/- 5.30, P < 0.01). The difference between tumor volume of [(68) Ga]pentixafor (TVpentixafor) and tumor volume of [F-18]FDG (TVFDG) showed no significance (median: 16.01 vs. 9.56, P = 0.332). In the detection of suspected metastatic cervical lymph nodes (CLNs), [(68) Ga]pentixafor PET possessed a lower SUVmax than [F-18]FDG PET/CT (SUVmax: 6.86 +/- 2.63 vs. 10.39 +/- 5.28, P < 0.01), but there was no significant difference in the detection rate between [(68) Ga]pentixafor and [F-18]FDG PET/CT (96 vs. 98, P = 0.613).<br /> Conclusions [(68) Ga]pentixafor is a promising imaging tracer for detecting primary and metastatic NPC. [(68) Ga]pentixafor PET/CT is comparable to [F-18]FDG PET/CT in the detection rate of primary tumors and metastatic cervical lymph nodes in nasopharyngeal carcinoma, but [(68) Ga]pentixafor uptake was heterogeneous. [(68) Ga]pentixafor PET/CT may help select patients most likely to benefit from CXCR4-directed endoradiotherapy. <bold>Clinical trial registration No.:</bold> ChiCTR2200065902