mpMRI may improve sensitivity and specificity of low dose short time 18F-PSMA 1007 imaging on a digital PET/CT scanner in low and medium risk prostate cancer patients after radical prostatectomy with biochemical recurrence at ultra-low PSA
mpMRI may improve sensitivity and specificity of low dose short time 18F-PSMA 1007 imaging on a digital PET/CT scanner in low and medium risk prostate cancer patients after radical prostatectomy with biochemical recurrence at ultra-low PSA
H. Falińska (1,2), M. Dziuk (1,2) 1. Military institute of Medicine National Research Institute, Warsaw, Poland 2. Affidea Poland
MRI has an established role in prostate cancer local recurrence detection. PSMA PET/CT with various tracers available is also a highly accurate method for the PC recurrent disease (especially if new digital scanners are used, that allow for low-dose ultra-fast PET imaging). However the role of both methods was assessed mainly in unselected population that included high and low risk patients. High Gleason score patients have unfavorable prognosis and higher metastasis potential The aim of this prospective study is to evaluate detection rates of recurrent prostate cancer by 18F-PSMA 1007 PET/CT and mpMRI in patients with low and medium risk prostate cancer Gleason up to 7 after radical prostatectomy.
16 males after radical prostatectomy and no radiotherapy with biochemical recurrence were enrolled. mpMRI (T2W imaging, diffusion-weighted imaging and dynamic contrast-enhanced imaging using 1.5T) of the pelvis was performed in all patients. 18F-PSMA-1007 with low dose 1 MBq /kg on a digital PET/CT scanner was acquired for 7 minutes. For MRI PI-RR criteria were employed to detect the recurrence. For PET/CT 5 point semiquantitative scale (based on PROMISE trial) was used to match the PI-RR findings. The patients were followed up for 1 year after last MR or PET/CT imaging.
Fig.1 mpMRI, vesicourethral anastomosis, very low likelihood of recurrence.
Fig.3 18F-PSMA 1007 PET/CT, liver-dominant excretion. No pathological uptake in postoperative bed.
There were 12 patents with Gleason 7 and 4 with Gleason 6. All had biochemical recurrence with the median of PSA was 0,35 ng/ml. The median of PI-RR was 2 and there was only 1 lymph node metastasis detected by MR and bony metastases in 2 patients. The median PET local recurrence score was 1,5 and there were regional nodal metastases found in 4 patients and distant metastases in 7 pts.
Fig.4
Fig.5 18F-PSMA 1007 PET/CT. Local recurrence.
Fig.6 mpMRI (the same patient as in fig.5). Local recurrence, two lesions, PI-RR 5.
Adding pelvic mpMR to 18F-PSMA new digital PET/CT whole body low dose imaging may improve the accuracy of the local disease detection and bony metastases in low and medium risk prostate cancer with biochemical recurrence at ultra low levels of PSA.
Fig.7 18F-PSMA 1007 PET/CT, mpMRI. PET/CT: local recurrence, regional and distant lymph nodes. mpMRI: only one lesion PI-RR 3, no enlarged lymph nodes in pelvis. PET/CT advantage.
Fig.8 18F-PSMA 1007 PET/CT, mpMRI. PET/CT: no visible pathological uptake - false negative result due to high urine activity (up to 15% of patients show urinaty excretion of 18F-PSMA). mpMRI: PI-RR 5. mpMRI advantage.
