Locoregional staging and focal therapy planning for prostate cancer: is PSMA PET/CT superior to MRI?

Both MRI and PSMA PET/CT are often utilized for staging of intermediate-risk (IR) and high-risk (HR) prostate cancer (PCa). Recent studies found that PSMA PET/CT was superior to MRI in correctly identifying final pathological tumor stage, dominant nodule, extraprostatic extension (EPE), and small areas of clinically significant PCa. We sought to determine if PSMA PET/CT was superior to MRI in both locoregional staging of PCa and potential focal therapy planning.

We retrospectively analyzed our prospectively collected, IRB-approved database of all patients who underwent prostatectomy at one institution between 10/1/2019-2/29/2024. Patients were excluded if they did not pre-operatively undergo both MRI and PSMA PET/CT. 2 × 2 tables were used to compare each modality to the "gold standard" of prostatectomy specimen in both the proper detection of laterality and presence of EPE. Sensitivities and specificities were compared using a chi-squared test. HR v. IR groups were compared using a Wilcoxon rank sum test for continuous variables and Fisher's exact test for categorical variables. Results were considered significant at p < 0.05.

580 patients underwent prostatectomy within the specified timeframe. 78 patients met inclusion criteria. MRI was more sensitive in the detection of EPE than PSMA PET/CT (23.5% v. 7.8%, p = 0.0294). MRI and PSMA PET/CT were similar in the specificity of EPE detection. In the identification of laterality, MRI was more specific (86.7% v. 56.7%, p = 0.0099), while sensitivities were similar between the modalities.

MRI was superior to PSMA PET/CT in the proper detection of both EPE and laterality in patients with IR and HR PCa.