A prospective head-to-head comparison of [ 68 Ga]Ga-P16-093 and [ 68 Ga]Ga-PSMA-11 PET/CT in patients with primary prostate cancer

Purpose We aimed to compare the diagnostic performance and biodistribution of two similar PET agents, [ 68 Ga]Ga-P16-093 and [ 68 Ga]Ga-PSMA-11, in the same group of primary prostate cancer (PCa) patients. Methods Fifty patients with untreated, histologically confirmed PCa by needle biopsy were enrolled. Each patient underwent [ 68 Ga]Ga-P16-093 and [ 68 Ga]Ga-PSMA-11 PET/CT within a week. In addition to visual analysis, the standardized uptake value (SUV) was measured for semiquantitative comparison and correlation analysis. Results [ 68 Ga]Ga-P16-093 PET/CT detected more positive tumors than [ 68 Ga]Ga-PSMA-11 PET/CT (202 vs. 190, P = 0.002), both for intraprostatic lesions (48 vs. 41, P = 0.016) and metastatic lesions (154 vs. 149, P = 0.125), especially for intraprostatic lesions in low- and intermediate-risk PCa patients (21/23 vs. 15/23, P = 0.031). Furthermore, [ 68 Ga]Ga-P16-093 PET/CT exhibited a significantly higher SUVmax for most matched tumors (13.7 ± 10.2 vs. 11.4 ± 8.3, P < 0.001). For normal organs, [ 68 Ga]Ga-P16-093 PET/CT showed significantly lower activity in the kidney (SUVmean: 20.1 ± 6.1 vs . 29.3 ± 9.1, P < 0.001) and urinary bladder (SUVmean: 6.5 ± 7.1 vs . 20.9 ± 17.4, P < 0.001), but displayed a higher uptake in the parotid gland (SUVmean: 8.7 ± 2.6 vs. 7.6 ± 2.1, P < 0.001), liver (SUVmean: 7.0 ± 1.9 vs. 3.7 ± 1.3, P < 0.001), and spleen (SUVmean: 8.2 ± 3.0 vs. 5.2 ± 2.2, P < 0.001) than [ 68 Ga]Ga-PSMA-11 PET/CT. Conclusion [ 68 Ga]Ga-P16-093 PET/CT demonstrated higher tumor uptake and better tumor detectability than [ 68 Ga]Ga-PSMA-11 PET/CT, especially in low- and intermediate-risk PCa patients, which indicated that [ 68 Ga]Ga-P16-093 may serve as an alternative agent for detection of PCa. Trial registration 68 Ga-P16-093 and 68 Ga-PSMA-11 PET/CT Imaging in the Same Group of Primary Prostate Cancer Patients (NCT05324332, Registered 12 April 2022, retrospectively registered). URL of registry https://clinicaltrials.gov/ct2/show/NCT05324332 .