Ziel/Aim:
The superior diagnostic accuracy provided by 68Ga-PSMA PET could potentially improve treatment stratification in patients with biochemical recurrence (BCR) of prostate cancer. Therefore, we evaluated the impact of 68Ga-PSMA and 11C-choline PET/CT with diagnostic contrast enhanced CT in regards to curative radiotherapy (RT) options including local treatment of oligometastases.
Methodik/Methods:
Eighty-three patients with BCR after radical prostatectomy +/- salvage radiotherapy (SRT) receiving both 68Ga-PSMA and 11C-choline PET/CT within the same day were included. 11C-choline PET/CT was combined with a diagnostic CT, while a low-dose CT was acquired for attenuation correction of the 68Ga-PSMA PET. Different investigators assessed the TNM-stage using diagnostic CT blinded to PET data and both PET examinations with diagnostic CT. Ten treatment routines were defined according to current practice and assigned to the patients using CT or PET results.
Ergebnisse/Results:
In 72.3% of the patients both PET-examinations led to concordant TNM-staging, while results were congruent between 68Ga-PSMA-PET and diagnostic CT only in 36.1%. Divergent findings between the methods may lead to “wrong” treatment and additional costs. We defined 68Ga-PSMA-PET as gold standard and found cost-effectiveness for 68Ga-PSMA-PET if additional costs do not exceed 3,843 € compared to CT. Similar to the “number needed to treat” we determined a “number needed to image (NNI)” to avoid one “wrong” treatment for a patient. The NNI was 4 for 11C-choline PET/CT and 2 for CT compared to 68Ga-PSMA-PET. In around 50% of the patients with previous RT the staging by 68Ga-PSMA-PET/CT enabled curative options instead of palliative ADT.
Schlussfolgerungen/Conclusions:
The known benefit of 68Ga-PSMA PET/CT over other methods is not only cost-effective but also enables application of curative treatment in many patients and should be recommended for staging of prostate cancer patients with BCR.
