Hypothesis / aims of study
To assess the effectiveness of 68Ga-PSMA-PET/CT (Gallium-68 Prostate Specific Membrane Antigen (PSMA)- N,N′-bis[2-hydroxy-5(carboxyethyl)benzyl]ethylenediamine-N,N′-diacetic acid (HBED-CC)/ positron emission tomography-computed tomography) as a standalone imaging modality compared to conventional imaging techniques for staging intermediate- and high-risk prostate cancer
Study design, materials and methods
Patients with biopsy-confirmed intermediate- and high-risk prostate adenocarcinoma were enrolled between July 2019 and May 2023. Each patient underwent conventional staging, which included multiparametric MRI (mpMRI), a Technetium-99m methyl diphosphonate (99mTc-MDP) bone scan, and CT, followed by 68Ga-PSMA-PET/CT. The diagnostic performance, sensitivity, and specificity of 68Ga-PSMA-PET/CT were then compared with those of conventional imaging.
Results
Out of 285 registered patients, 169 were included after obtaining informed consent. The mean age of the patients was 65.5 years, with a median serum PSA level of 23.08 ng/ml. The majority (147) were classified as high-risk, while 22 were intermediate-risk. 68Ga-PSMA-PET/CT demonstrated statistically significant superiority over conventional imaging in detecting regional lymph node involvement (37.8% vs. 18.3%), non-regional lymph node metastases (17.2% vs. 5.9%), and bone metastases (23% vs. 16.5%). It showed comparable performance to conventional imaging in assessing seminal vesicle invasion and visceral metastases. Additionally, PSMA-PET/CT upstaged nodal (N) and metastatic (M) status in 10.6% and 8.8% of cases, respectively. In the 8.8% of patients upstaged to M1, treatment intent was changed from curative to palliative.
Interpretation of results
In this study of 169 patients, 68Ga-PSMA-PET/CT showed significant superiority over conventional imaging in detecting lymph node and bone metastases, and led to nodal and metastatic upstaging in a notable number of cases. Importantly, in 8.8% of patients, PSMA-PET/CT findings changed treatment intent from curative to palliative.
Concluding message
68Ga-PSMA-PET/CT exhibits superior detection rates over conventional imaging, particularly for regional lymph node, bone, and distant metastases. This modality significantly improves staging accuracy, which is essential for precise and timely treatment planning, thereby playing a critical role in the detection and management of prostate cancer.