From the Guidelines
PSMA PET CT is the recommended imaging modality for detecting prostate cancer, particularly for patients with suspected recurrence after treatment, initial staging of intermediate to high-risk prostate cancer, and monitoring treatment response, due to its superior sensitivity and specificity compared to conventional imaging, as demonstrated in recent studies 1. The procedure involves an intravenous injection of a radiotracer, such as gallium-68 PSMA-11 or fluorine-18 PSMA-1007, about 60 minutes before imaging. Patients should stay well-hydrated before the scan but may need to fast for 4-6 hours. The entire procedure takes about 2 hours, with the actual scanning time being 20-30 minutes. Some key points to consider when using PSMA PET CT include:
- It can detect smaller cancer deposits, even when PSA levels are low (0.2-0.5 ng/mL), allowing for earlier detection of recurrence and more precise treatment planning 1.
- It is superior to conventional imaging, with higher detection rates and better sensitivity and specificity, particularly in patients with high-risk prostate cancer 1.
- It can be used instead of or after negative conventional imaging, and is preferred over conventional imaging alone in patients with suspected biochemical recurrence after radical prostatectomy 1.
- The availability of PET tracers is increasing, but PET/CT is not currently available everywhere, and the availability of individual tracers varies locally 1. In terms of specific patient populations, PSMA PET CT is particularly useful for:
- Patients with suspected prostate cancer recurrence after treatment, as it can detect smaller cancer deposits and allow for earlier detection of recurrence 1.
- Patients with intermediate to high-risk prostate cancer, as it can provide more accurate staging and better guidance for treatment decisions 1.
- Patients with biochemical recurrence after radical prostatectomy, as it can be used to detect and localize recurrent disease, and guide salvage therapy 1.
From the Research
PSMA PET CT Overview
- PSMA PET CT is an emerging imaging modality used to assess the burden of prostate cancer, particularly in biochemically recurrent or advanced disease 2.
- It provides the ability to selectively identify and localize metastatic prostate cancer cells, which can change patient management 2.
Diagnostic Performance
- The overall percentage of positive 68Ga-PSMA PET among patients was 40% for primary staging and 76% for biochemical recurrence (BCR) 2.
- Positive 68Ga-PSMA PET scans for BCR patients increased with pre-PET PSA levels, with 42%, 58%, 76%, and 95% scans being positive for PSA categories 0-0.2,0.2-1-2, and >2 ng/ml, respectively 2.
- The summary sensitivity and specificity of 68Ga-PSMA PET were 86% and 86% on per-patient analysis, and 80% and 97% on per-lesion analysis, respectively 2.
Clinical Impact
- PSMA PET/CT results led to changes in therapeutic management in 56.8% of patients with biochemical recurrence after primary treatment for prostate cancer 3.
- The use of PSMA PET/CT in patients with recurrent prostate cancer after primary radical treatment can help identify recurrence localization, even at very low levels of PSA (<0.5 ng/mL) 4.
- PSMA PET/CT has been shown to be superior to conventional imaging techniques (CT and MRI) in detecting recurrent prostate cancer 4.
Emerging Applications
- PSMA PET/CT has been explored for its potential use in detecting non-prostatic conditions, such as esophageal cancer and hepatocellular carcinoma 5.
- However, further workup is warranted in cases of uptake in atypical locations to avoid premature conclusions of metastatic prostate disease 5.
Comparison with Other Imaging Modalities
- 68Ga-PSMA PET/CT has been compared to [68Ga]Ga-PSMA-11 PET/CT and [89Zr]Zr-PSMA-617 PET/CT, with the latter showing promising results in detecting prostate cancer lesions at later time points 6.
- PSMA PET/CT has been shown to outperform choline-based PET scan in detecting recurrent prostate cancer 2, 4.