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

This study aimed to explore the feasibility of [⁶⁸ Ga]pentixafor positron emission tomography/computed tomography (PET/CT) in patients with nasopharyngeal carcinoma (NPC).

This prospective study included patients with NPC who underwent [⁶⁸ Ga]pentixafor PET/CT and 2-[¹⁸F]fuoro-2-deoxy-D-glucose ([¹⁸F]FDG) PET/CT within one week between November 2022 and March 2023. The [⁶⁸ Ga]pentixafor and [¹⁸F]FDG uptakes in primary and metastatic lesions were measured and compared.

Twenty-five participants (21 patients for initial stage and four patients for recurrence detection) were enrolled in our study. The participants underwent [¹⁸F]FDG PET/CT and [⁶⁸ Ga]pentixafor PET/CT. [⁶⁸ Ga]pentixafor PET/CT had the same detection rate as [¹⁸F]FDG for primary tumor (96% vs. 96%). The [⁶⁸ Ga]pentixafor maximum standard uptake value (SUV_max) and target-to-background ratio (TBR) of primary tumors were lower than those of [¹⁸F]FDG (SUV_max: 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 (TV_pentixafor) and tumor volume of [¹⁸F]FDG (TV_FDG) 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 SUV_max than [¹⁸F]FDG PET/CT (SUV_max: 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 [¹⁸F]FDG PET/CT (96 vs. 98, P = 0.613).

[⁶⁸ Ga]pentixafor is a promising imaging tracer for detecting primary and metastatic NPC. [⁶⁸ Ga]pentixafor PET/CT is comparable to [¹⁸F]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.

Clinical trial registration No.: ChiCTR2200065902