Ziel/Aim:
The aim of the study was to retrospectively assess the PSMA-avid distribution of PCa
disease prior to planned definitive treatment in 68Ga-PSMA I&T PET/CT.
Methodik/Methods:
Eighty two patients with biopsy proven, treatment-naive PCa were included in the study.
All patients underwent 68Ga-PSMA I&T PET/CT (PSMA I&T SCINTOMICS GmbH, Fürstenfeldbruck, Germany) between September
2016 and August 2018 for primary staging of the disease. Focal radiotracer accumulation
within the prostate gland was considered as positive primary tumour uptake, whereas
focally increased uptake within the lymphatic drainage areas was regarded as lymph
node metastasis (LNMs). Bone metastasis (BMs) or other distant metastasis were also
reported.
Ergebnisse/Results:
The patients main characteristics were: mean age was 66.7 ± 7.3 years (range 53 –
83), median Gleason score (GSC) 7 (range 6 – 10), median PSA level 11.0 ng/ml (range
0.7 – 872.5). Low-risk disease was present in 11, intermediate-risk in 32, and high-risk
in 39 patients (according to D'Amico classification). Sixty-six (80.5%) patients presented
with positive primary tumour uptake. PSMA positive LNs were reported in 17 patients
(20.7%). Distant metastases were found in 12 (14.6%) patients, predominantly in bones,
only one (1.2%) patient had lung metastasis. Overall, regional disease only (prostate
gland + local extension) was present in 45 (54.9%) patients, while extraprostatic
disease was present in 23 (28.0%) patients (4 of them had intermediate- and 19 had
high-risk PCa). The presence of LNMs or distant metastases rose significantly with
GSC 8 or higher. Negative studies were stated in 14 patients, of whom 12 had GSC 6
or 7. We found a significant positive correlation (r = 0.51, p = 0.000001) between
the SUVmax of primary tumour uptake and PSA level, and between primary tumour SUVmax and GSC (r = 0.38, p = 0.00024). Primary tumour uptake was also significantly higher
in patients with LNMs (mean SUVmax 24.9 ± 16.0, n = 22) vs. patients without LNMs (mean SUVmax 14.1 ± 12.6, n = 60, p = 0.039).
Schlussfolgerungen/Conclusions:
68Ga-PSMA I&T PET/CT is a useful tool in primary staging of PCa with detection rates
and PSMA expression of PCa lesions rising with GSC, PSA level and risk group of disease.