Introduction

Functional 68Ga-labelled PSMA or morphologic mpMRI-imaging detects intraprostatic prostate cancer (PCa) foci. To assess the diagnostic performance of 68Ga-PSMA-PET-CT or mpMRI alone and their combination for characterising side specific intraprostatic PCa cancer lesions, when performed in a sequential setting.

Methods

Overall, 30 patients with biopsy proven prostate cancer received a 68Ga-PSMA-PET-CT and mpMRI imaging prior radical prostatectomy (RP). Preoperative intraprostatic findings of both different modalities and their combination were compared with histological work up after RP. Lesions were classified positive with mpMRI (Likert scale >3) and PET/CT foci with elevated SUVmax (focus vs. background).

Results

Median PSA was 9.0 ng/ml (IQR 4.2-35.7). MpMRI and PET/CT identified (IQR) 2 (1-2) tumorfoci. Sidespecific sensitivity of mpMRI, PET/CT and the combined imaging approach was 83.3% (95%CI 70.7-92.1%), 79.6% (95%CI 66.5-89.4%) and 94.4% (95%CI 54.5-98.8%). Overall sidespecific specifity was 66.7% (95%CI 22.3-95.7%). Sensitivity per patient was 63.3% (95%CI 46.7-80% mpMRI), 56.7% (95%CI 40.0-73.3% PET/CT) and 83.3% (95%CI 70.0-96.7%) for the combined approach.

Conclusions

Combining functional 68Ga-PSMA-PET and morphologic mpMRI imaging increases the ability to detect intraprostatic tumour lesions without affecting the specifity. Our data demonstrate, that the sequential approach provides a tailored use of both imaging modalities, which reaches similar diagnostic performances as reported in series using whole-in-one MRI-PSMA/PET scanners. Further studies are necessary to validate these findings in patients harbouring low risk disease only.

Funding

none