A head-to-head comparison of [Ga]Ga-DOTATATE and [Ga]Ga-FAPI PET/CT in patients with nasopharyngeal carcinoma: a single-center, prospective study.

Purpose: We aimed to compare the staging efficiency of [Ga]Ga-DOTATATE and [Ga]Ga-FAPI PET/CT in nasopharyngeal carcinoma (NPC) patients.

Methods: Thirty-nine patients with pathologically confirmed NPC were enrolled in this prospective study. Each patient underwent paired [Ga]Ga-DOTATATE and [Ga]Ga-FAPI PET/CT on 2 successive days. The accuracy of two PET/CT for assessing T, N, and M stages was compared by using head-and-neck MRI, histopathologic diagnosis and follow-up results as reference standards. The radiotracer uptake derived from two PETs was also compared.

Results: For treatment-naïve patients, [Ga]Ga-DOTATATE PET/CT showed identical sensitivity for the primary tumours but clearer tumor delineation induced by higher tumour-to-background (TBR) ratio (19.1 ± 8.7 vs. 12.4 ± 7.7, P = 0.003), compared with [Ga]Ga-FAPI PET/CT. Regarding cervical lymph node (CLN) metastases, [Ga]Ga-DOTATATE PET had significantly better sensitivity and accuracy based on neck sides (98% vs. 82%, P < 0.001; 99% vs. 88% P = 0.008), neck levels (98% vs. 78%, 99% vs. 97%; both P < 0.001) and individual nodes (89% vs. 56%, 91% vs. 76%; both P < 0.001), and higher TBR (8.1 ± 4.1 vs. 6.3 ± 3.7, P < 0.001). Additionally, [Ga]Ga-DOTATATE PET/CT revealed higher sensitivity and accuracy for distant metastases (96% vs. 53%, 95% vs. 52%; both P < 0.001), particularly in bone metastases (99% vs. 49%, 97% vs. 49%; both P < 0.001). For post-treatment patients, [Ga]Ga-DOTATATE PET/CT identified one more true-negative case than [Ga]Ga-FAPI PET/CT.

Conclusion: [Ga]Ga-DOTATATE PET/CT performed better than [Ga]Ga-FAPI PET/CT in visualizing the primary tumours, detecting the metastatic lesions and identifying the local recurrence, suggesting [Ga]Ga-DOTATATE PET/CT may be superior to [Ga]Ga-FAPI PET/CT for NPC staging.