2.2 Clinical Diagnosis and Staging Applications
2.2.1 Initial Diagnosis and Staging When using PSMAPET/CT for detection, regardless of the size of the lesion, it can simultaneously evaluate primary prostate tumors, visceral organs, bones, and lymph nodes for metastatic lesions, significantly improving the diagnostic efficiency of initial staging (6). The application of PSMA PET/CT holds a central position in the staging of intermediate- to high-risk prostate cancer (7). For patients with clinically suspected prostate cancer (persistent elevation of PSA and/or positive DRE), if the mpMRI PI-RADS score is 3 or greater than 3 but with a negative biopsy, the use of PSMA PET/CT is recommended for auxiliary diagnosis (7). For intermediate- to high-risk Pca patients, the combination of PSMA PET/CT and multiparametric MRI (mpMRI) has become the standard clinical staging protocol, especially when there is suspicion of extracapsular invasion or seminal vesicle involvement. In such cases, integrated PSMA PET/MR imaging is recommended to enhance the accuracy of local invasion assessment (7). However, in PSMA-negative PCa patients, the role of PSMA PET is limited (6, 11-13).
2.2.2 Initial Assessment of Suspected Lesions In men with clinical suspicion of PCa and MRI (PI-RADS ≤ 3), the application of a novel diagnostic model combining PSMA-PET, serum fPSA/tPSA, and other markers can reduce unnecessary biopsies by 78% (14).
2.2.3 Evaluation of Intermediate- to High-Risk Pca PSMA-PET/CT has a significant diagnostic advantage in assessing high-risk PCa patients. The accuracy of 68Ga-PSMA-11 PET/CT in staging initially diagnosed high-risk prostate cancer is 92%, compared to 65% for traditional imaging (3, 8). Another multicenter study also demonstrated that 18F-DCFPyL PET/CT has high diagnostic performance in lymph node staging (3, 9). Moreover, 68Ga-PSMA-11 PET/CT detects an additional 25% of lymph node metastases and 6% of bone metastases compared to traditional imaging, leading to a change in the clinical treatment plan for 21% of patients (3, 15). Additionally, both 68Ga-PSMA-11 and 18F-AlF-PSMA-11 PET/CT have high diagnostic value in detecting metastatic disease in initially screened intermediate- to high-risk prostate cancer patients (16). Therefore, for the initial staging of intermediate- to high-risk prostate cancer, the use of PSMAPET/CT is recommended (3).
