Simultaneous whole-body PET/MRI with integrated multiparametric MRI for primary staging of high- risk prostate cancer

Zielsetzung Positron emission tomography/magnetic resonance imaging (PET/MRI) is a promising diagnostic tool of recurrent prostate cancer (PC), but its role in primary staging of high risk PC (hrPC) is not well defined. The aim was to compare the diagnostic accuracy for T- and N-staging of PET blinded reading (PBR) and PET/MRI.

Material und Methoden In this prospective study, hrPC patients scheduled to radical prostatectomy (RPx) with extended lymphadenectomy (eLND) were staged with PET/MRI and either 68Ga-PSMA-11 or 11C-choline including simultaneous multiparametric MRI (mpMRI). Images were assessed in two sessions, first as PBR (mpMRI/MRI) and second as PET/MRI. Prostate Imaging Reporting and Data System criteria (PI-RADS v2) was used for T-staging. Results were correlated with the exact anatomical localization and extension as defined by histopathology. Diagnostic accuracy of cTN stage according to PBR was compared to pathological pTN stage as reference standard.

Ergebnisse 34 patients underwent PET/MRI of 68Ga-PSMA-11 (n=17) or 11C-choline (n=17). 24 patients meeting the inclusion criteria of localized disease ± nodal disease based on imaging results underwent RPx and eLND, whereas 10 patients were excluded from analysis due to metastatic disease. T-stage was best defined by mpMRI with underestimation of tumor lesion size by PET for both tracers. N-stage yielded a per patient sensitivity/specificity comparable to PBR.

Schlußfolgerungen MpMRI is the primary modality for T-staging in hrPC as PET underestimated T-stage in direct comparison to final pathology. In this selected study cohort MRI shows no inferiority compared to PET/MRI considering N-staging.