[68Ga]PSMA PET/CT Improves Initial Staging and Management Plan of Patients with High-Risk Prostate Cancer

Abstract

Purpose: In this retrospective study, we compared the diagnostic value of ⁶⁸Gallium prostate-specific membrane antigen positron emission tomography computed tomography ([⁶⁸Ga]PSMA PET/CT) in primary staging of patients with high-risk prostate cancer (PCa), in comparison to CT, magnetic resonance imaging (MRI), and bone scans, and we explored its overall impact on patients' management plan.

Procedures: Patients with pathological confirmation of PCa with high-risk disease were included in this study. Information on patient demographics, clinical and histopathological findings with Gleason score and initial prostate specific antigen PSA levels, and radiological findings for CT, MRI, bone scan, and [⁶⁸Ga]PSMA PET/CT were retrieved. We stratified the concordance and discordance of each imaging modality on per-patient and per-lesion-site bases.

Results: Twenty-one patients with high-risk disease were included in this study. [⁶⁸Ga]PSMA PET/CT revealed a significantly higher concordance rate (90 %) compared to the concordance rates of bone scan (75 %), MRI (73 %), and CT (60 %). [⁶⁸Ga]PSMA PET/CT had a similar accuracy to MRI in detecting prostate lesions but a higher accuracy for suspicious pelvic lymph nodes (95.2 % vs. 80 %). It also superseded CT scan in detecting suspicious pelvic lymph nodes (95.2 % vs. 75 %) and extra-pelvic lymph nodes (100 % vs. 75 %), as well as bone lesions via bone scan (100 % vs. 62.5 %). [⁶⁸Ga]PSMA PET/CT changed the management in 11 patients (52 %).

Conclusions: [⁶⁸Ga]PSMA PET/CT is an invaluable imaging modality in the assessment of primary high-risk PCa with great potential for the detection of lymph node spread and bone metastases that would impact the management plan.

Keywords: Bone scan; CT scan; High risk; MRI; Nuclear medicine; PET/CT; PSMA; Primary staging; Prostate cancer; Theranostics.