Comparing digital to analog prostate-specific membrane antigen-targeted piflufolastat 18F PET/CT in prostate cancer patients in early biochemical failure

Abstract

Purpose Prostate-specific membrane antigen (PSMA) positron emission tomography/computer tomography (PET/CT) in prostate cancer patients with biochemical failure(BCF) showslimited sensitivity when the prostate-specific antigen(PSA) <0.5 ng/mL. The development of digital PET/CT has greatly improved smaller lesion detection. This study's goal was to compare the performance and clinical value of PSMAtargeted piflufolastat PET/CT for prostate cancer BCF with digital versus analog PET/CT. MethodsIn this retrospective study, all piflufolastat PET/CT scans in subjects with PSA ≤ 3.0 ng/mL who were referred for prostate cancer BCF were included. The performance characteristics of 171 analog PET/ CT studies in 155 subjects from May 2017 to January 2020 and 106 digital PET/CT studies in 103 subjects from February 2020 to December 2020 were compared. Lesions were considered malignant if they did not match the known physiological distribution of piflufolastat and did not represent uptake in benign lesions. PSMA PET/CT studies were considered positive if at least one malignant lesion was detected and negative if none were detected. ResultsDigital piflufolastat PET/CT outperformed analog piflufolastat PET/CT in subjects with PSA < 0.5 ng/ mL with a positivity rate of 69% versus 37%, respectively. In patients with PSA ≥ 0.5 ng/mL, both technologies performed similarly. There was no statistically significant difference between the number or size of piflufolastat-avid lesions detected per PET/CT study. ConclusionIn prostate cancer patients with BCF and PSA < 0.5 ng/mL, digital piflufolastat PET/CT has a higher detection rate of malignant lesions than analog piflufolastat PET/CT.

Comparison of Digital versus Analog 68Ga-PSMA-11 PET/CT Performance in Hormone-Sensitive Prostate Cancer Patients with Early Biochemical Recurrence or Persistence after Radical Treatment

“…Despite this evidence, a previous study did not show a significant difference in lesion size between dPET and aPET, although reporting a higher tumor-to-background ratio (TBR) for dPET, therefore resulting in an improved lesion detectability nonetheless [35]. This aspect should also be further investigated using other PSMA tracers, such as 18 F-DCFPyL [38].…”

“…dPET also identified a significantly higher number of pathologic findings (PSMA-RADS ≥ 3) per patient and more multi-metastatic cases (>3 lesions) compared to aPET. Previous literature studies have compared the performance of digital and analog PET/CT in prostate cancer patients [35][36][37][38][39]. Specifically, Alberts et al, in a retrospective evaluation of two matched cohorts of BCR Pca patients undergoing 68 Ga-PSMA-11 imaging (aPET: 88, dPET: 88), found that dPET identified a greater number of pathological findings.…”

“…A prospective study by Duan et al on a lower sample size (n = 58) also reported dPET to be able to identify additional sites of recurrence, with higher sensitivity and specificity at lower PSA ranges, despite not reaching statistical significance [37]. The comparative performance of dPET and aPET in Pca patients has also been evaluated using other radiotracers such as 18 F-DCFPyL, where dPET outperformed aPET in subjects with biochemical failure and PSA < 0.5 ng/mL (69% vs. 37%) while no significant differences were found at higher PSA values [38]. Contrary to PSMA-based radioligands, dPET was not able to achieve a superior diagnostic performance when using 18 F-Fluorocholine for pelvic nodal staging of intermediate to high-risk PCa patients using histopathology as reference standard [39].…”