18F-PSMA-PET/CT in comparison with whole-body MRI and combination of conventional CT and bone scintigraphy for detection of recurrent disease in prostate cancer patients with rising PSA levels after initial definitive treatment.

BACKGROUND: The purpose of this study was to compare the diagnostic performance of radiolabeled prostate-specific membrane antigen-targeted positron emission tomography/computed tomography (PSMA-PET/CT) with 18F, whole-body magnetic resonance imaging (WB-MRI), including diffusion-weighted imaging (DWI) and a combination of conventional computed tomography and bone scintigraphy (CT/BS) for the detection of recurrent lesions in patients with prostate cancer with rising PSA levels following initial definitive treatment.

METHODS: This retrospective study used part of the dataset from a previous phase 2 study conducted between February 2019 and March 2022, which evaluated the detection efficacy of 18F-FSU-880 PSMA-PET/CT in 72 patients with suspected recurrent prostate cancer after definitive treatment. Of these, 35 patients (age 56-82 years, PSA level 0.24-40.00 ng/ml) who underwent both PSMA-PET/CT and WB-MRI were reviewed by six radiologists. Sensitivity, specificity, and overall accuracy were compared using McNemar's test, and positive predictive value was compared using Fisher's exact test.

RESULTS: Total 132 true-positive prostate cancer lesions were detected in 23 of 35 patients (66%). The sensitivity of PSMA-PET/CT (100%) was significantly higher than those of both WB-MRI (57%) and CT/BS (32%) in the per-patient analysis (p = 0.002 and p < 0.001, respectively). In the per-lesion analysis, the sensitivity of PSMA-PET/CT (88%) was significantly higher than those of WB-MRI (44%) and CT/BS (6%) (p < 0.001 and p < 0.001, respectively).

CONCLUSIONS: 18F-FSU-880 PSMA-PET/CT showed a more favorable diagnostic performance, especially in terms of sensitivity, than WB-MRI and CT/BS in detecting recurrent disease in patients with prostate cancer after definitive treatment.