Prostate-specific membrane antigen (PSMA) positron emission tomography/computed tomography (PET/CT) may be more advantageous than multiparametric magnetic resonance imaging (mpMRI) for detecting biochemical recurrence (BCR) of prostate cancer (PCa), according to a new meta-analysis.
For the meta-analysis, recently published in Current Urology, researchers reviewed data from five comparative studies (including a total of 225 patients) examining the use of PSMA PET/CT and mpMRI for diagnosing PCa BCR in the same patient cohorts.
The researchers found that PSMA PET/CT had an overall positivity rate of 68 percent for detecting BCR of PCa in contrast to 56 percent for mpMRI. PSMA PET/CT also had a 44 percent positivity rate for lymph node metastasis in comparison to 25 percent for mpMRI, according to the meta-analysis authors.
“Evidence from this study suggests that PSMA PET/CT has a higher positivity detection rate for BCR and lymph node metastases than that of mpMRI,” wrote the meta-analysis co-authors Xinru Zhang, M.D., and Zhe Ma, M.D., who are affiliated with the Department of Ultrasound at the First Affiliated Hospital of Shandong First Medical University in Jinan, China.
(Editor's note: For additional content on prostate cancer imaging. click here.)
The meta-analysis authors said PET/CT has unique attributes that could facilitate earlier detection of PCa recurrence.
“Positron emission tomography/computed tomography is a novel diagnostic tool that has demonstrated its unique diagnostic properties in cancer, particularly for PCa. The ability to develop radio-labeled tracers for functional imaging based on PCa cell characteristics could potentially provide additional information by exploiting key features of these cells, such as metabolic activity, increased proliferation, and receptor expression,” added Zhang and Ma.
Three Key Takeaways
1. Higher detection rates with PSMA PET/CT. PSMA PET/CT demonstrates a higher positivity detection rate for biochemical recurrence (BCR) of prostate cancer (PCa) and lymph node metastases compared to multiparametric MRI (mpMRI). The meta-analysis reported a 68 percent positivity rate for BCR with PSMA PET/CT, compared to 56 percent with mpMRI, and a 44 percent positivity rate for lymph node metastasis compared to 25 percent with mpMRI.
2. Unique Diagnostic Attributes of PET/CT. The researchers noted the potential of PET radiolabeled tracers for functional imaging based on prostate cancer cell characteristics. This allows for more detail into features like metabolic activity and receptor expression, potentially facilitating earlier detection of recurrence.
3. Limitations and Considerations. The meta-analysis highlighted limitations, including the low number of reviewed studies and lack of evaluation of benign lesions. The authors also cautioned against broad extrapolation of positivity rates due to study differences, such as biomarker thresholds and follow-up duration, which can impact results. There was no significant difference observed between PET/CT and mpMRI for detecting local PCa recurrence.
However, the researchers noted no significant difference between PET/CT and mpMRI in the detection of local PCa recurrence (37 percent vs. 38 percent).
Zhang and Ma also cautioned against broad extrapolation of the meta-analysis findings on positivity rates for PCa recurrence, noting a lack of acceptable levels of heterogeneity for both PET/CT and mpMRI after a sensitivity analysis. They also suggested that study differences with respect to biomarker thresholds and follow-up duration can impact results.
(Editor’s note: For related content, see “How Effective is mpMRI at Detecting PCa in Biopsy-Naïve Patients?,” “Detecting PCa Recurrence in African Americans: Can 18F-Flotufolastat Have an Impact?” and “SNMMI: PSMA-18F DCFPyL Changes Treatment for PCa Recurrence in Significant Number of Patients with Low PSAs.”)
In regard to limitations of the meta-analysis, the authors conceded the low number of reviewed studies. They also acknowledged that the meta-analysis did not include evaluation of benign lesions. The researchers also noted there was no assessment of accuracy or specificity rates for PET/CT or mpMRI.
