PSMA PET/CT facilitates improved accuracy with local staging of intermediate- and high-risk prostate cancer (PCa), according to a new comparative study.
For the retrospective study, recently published in the Journal of Nuclear Medicine, researchers compared prostate-specific membrane antigen (PSMA) positron emission tomography/computed tomography (PET/CT, gastrin-releasing peptide receptor (GRPR) PET/CT and multiparametric MRI (mpMRI) in 81 patients with intermediate- or high-risk PCa. The study authors also assessed the combination of PSMA PET/CT and mpMRI in this patient population.
The researchers found that PSMA PET/CT provided 20 percent higher accuracy than GRPR PET/CT in the staging of local prostate tumors (56 percent vs. 36 percent) and 25 percent higher sensitivity for extraprostatic extension (EPE) (61 percent vs. 36 percent). PSMA PET/CT also offered significantly higher sensitivity for bilateral intraprostatic disease (BID) than mpMRI or GRPR PET/CT (71 percent vs. 41 percent and 52 percent respectively) as well as superior accuracy in detecting acinar adenocarcinoma (58 percent vs. 39 percent and 34 percent respectively).
The study authors determined that combining PET/CT and mpMRI offered 20 percent higher accuracy in tumor staging (61 percent) in comparison to mpMRI alone (41 percent) and detection of BID (74 percent vs. 54 percent).
“The combination of PET/CT and MRI could improve diagnostic accuracy, reduce stage underestimation, and provide prognostic significance for BRFS. PSMA plus MRI performed as the most accurate among the 5 tests, retaining independent prognostic value when compared with the known factors. These suggest that PET/CT-based local stage can be incorporated into existing stratification models as an
important prognostic predictor, even when MRI is available,” noted lead study author Yujia Li, M.D., who is affiliated with the Department of Nuclear Medicine in Xiangya Hospital at Central South University in Changsha, China, and colleagues.
For Related Content
• PSMA PET/CT outperforms GRPR PET/CT and mpMRI for local staging.
In intermediate- and high-risk prostate cancer, PSMA PET/CT demonstrated higher accuracy for local tumor staging (56 percent vs. 36 percent with GRPR PET/CT) and greater sensitivity for extraprostatic extension (61 percent). It also showed superior detection of bilateral intraprostatic disease and acinar adenocarcinoma compared with both mpMRI and GRPR PET/CT.
• Combining PSMA PET/CT with mpMRI improves staging performance.
The integrated approach increased tumor staging accuracy by 20 percent compared with mpMRI alone (61 percent vs. 41 percent) and significantly improved detection of bilateral intraprostatic disease (74 percent vs. 54 percent), helping reduce the risk of local stage underestimation.
• Combined PSMA PET/CT and mpMRI staging ≥T3a independently predicts biochemical recurrence-free survival.
The study found that PSMA PET/CT and MRI-derived local staging of ≥T3a was independently associated with worse bRFS (HR 4.277), demonstrating stronger prognostic value than biopsy grade group >4 (HR 2.143) or PSA >20 ng/mL (HR 1.934). This suggests that integrated PET/MRI local staging may add incremental prognostic information beyond traditional clinicopathologic risk factors.
For predicting biochemical recurrence-free survival (bRFS), the study authors found that the combination of PSMA PET/CT and mpMRI local staging > T3a offered greater prognostic insight (hazard ratio of 4.277) than biopsy grade group > 4 (HR of 2.143) and prostate-specific antigen (PSA) level > 20 ng/mL (HR of 1.934).
“In the prognostic analysis, we provide the first evidence that PSMA plus MRI with a T3a or greater (staging) is independently associated with BRFS. This combined use may improve decision-making for nerve-sparing strategies or RP without intensified therapy, allowing for excluding men ineligible for these treatments, despite a slight reduction in specificity,” emphasized Li and colleagues.
(Editor’s note: For related content, see “Can an Integrated Approach with PSMA PET/CT and Prostate MRI Enhance Detection of Extraprostatic Extension?,” “Can PSMA PET Parameters Help Predict Toxicity and Outcomes in Patients Treated for mCRPC?” and “5T Prostate MRI Study Reveals Enhanced Image Quality and Detection.”)
Beyond the inherent limitations of a single-center retrospective study, the authors acknowledged the small cohort and the exclusion of low-risk patients. They also noted that results with the use of (68Ga)Ga-PSMA 617 may not be applicable to other PSMA ligands.
