Head-to-Head Comparison of ⁶⁸Ga-PSMA-11 with ¹⁸F-PSMA-1007 PET/CT in Staging Prostate Cancer Using Histopathology and Immunohistochemical Analysis as a Reference Standard

Abstract

18 F-PSMA-1007 is a novel prostate-specific membrane antigen (PSMA)-based radiopharmaceutical for imaging prostate cancer (PCa). The aim of this study was to compare the diagnostic accuracy of 18 F-PSMA-1007 with 68 Ga-PSMA-11 PET/CT in the same patients presenting with newly diagnosed intermediate-or high-risk PCa. Methods: Sixteen patients with intermediate-or high-risk PCa underwent 18 F-PSMA-1007 and 68 Ga-PSMA-11 PET/CT within 15 d. PET findings were compared between the 2 radiotracers and with reference-standard pathologic specimens obtained from radical prostatectomy. The Cohen κ-coefficient was used to assess the concordance between 18 F-PSMA-1007 and 68 Ga-PSMA-11 for detection of intraprostatic lesions. The McNemar test was used to assess agreement between intraprostatic PET/CT findings and histopathologic findings. Sensitivity, specificity, positive predictive value, and negative predictive value were reported for each radiotracer. SUV max was measured for all lesions, and tumor-to-background activity was calculated. Areas under receiver-operating-characteristic curves were calculated for discriminating diseased from nondiseased prostate segments, and optimal SUV cutoffs were calculated using the Youden index for each radiotracer. Results: PSMA-avid lesions in the prostate were identified in all 16 patients with an almost perfect concordance between the 2 tracers (κ ranged from 0.871 to 1). Aside from the dominant intraprostatic lesion, similarly detected by both radiotracers, a second less intense positive focus was detected in 4 patients only with 18 F-PSMA-1007. Three of these secondary foci were confirmed as Gleason grade 3 lesions, whereas the fourth was shown on pathologic examination to represent chronic prostatitis. Conclusion: This pilot study showed that both 18 F-PSMA-1007 and 68 Ga-PSMA-11 identify all dominant prostatic lesions in patients with intermediateor high-risk PCa at staging. 18 F-PSMA-1007, however, may detect additional low-grade lesions of limited clinical relevance.

PSA and PSA Kinetics Thresholds for the Presence of 68Ga-PSMA-11 PET/CT-Detectable Lesions in Patients with Biochemical Recurrent Prostate Cancer

“…Nevertheless, in 36% of the patients with positive scans, additional lesions were found, while using 18 F-PSMA vs. 68 Ga-PSMA [18]. Overall, the results of both methods were demonstrated to be similar [18]; this was also shown in a recent study, which compared 68 Ga-PSMA-11 and 18 F-PSMA-1007 in the case of staging PC [33].…”

Intraindividual comparison between 68Ga-PSMA-PET/CT and mpMRI for intraprostatic tumor delineation in patients with primary prostate cancer: a retrospective analysis in 101 patients

“…68 Ga-PSMA accumulation in the bladder intensifies background signal and thus aggravates tumor lesion delineation in areas adjacent to the bladder. New PSMA-tracers like 18 F-PSMA-1007 show lesser renal elimination and might further improve intraprostatic tumor lesions detection [36,37].…”

Prostate-specific membrane antigen positron emission tomography (PSMA-PET) for local staging of Prostate Cancer: A Systematic Review and Meta-Analysis

“…Furthermore, although we only assessed 68 Ga-based radioligands, there are other newer non-68 Ga-based radioligands which show promising results. For example, one comparative study for 18 F-PSMA-1007 and 68 Ga-PSMA-11 in 16 patients showed that 18 F-PSMA-1007 may potentially have higher detectability for low grade cancer (Gleason 3) than 68 Ga-PSMA-11 [41]. In another study that included 7 patients, 18 F-PSMA-1007 PET/MRI yielded a sensitivity and specificity of 100% each for determining SVI.…”