Histopathological Correlation of Robotic-Assisted Radical Prostatectomy Specimen with Simultaneous ⁶⁸GA-PSMA PET/MRI Findings in Cases of Adenocarcinoma Prostate

Background and Aims: 68 Ga-PSMA PET represents a reasonable biomarker for presence of cancer of prostate (CaP). 68 Ga-PSMA PET combined with simultaneous ‘multiparametric MRI’ (mpMRI) has the potential to be used for the detection and localisation of primary prostate cancer. It is therefore essential to correlate the histopathological findings of robotic-assisted radical prostatectomy (RARP) specimens with pre-operative PSMA PET/MRI. In addition, imaging with PSMA could be useful in estimating the aggressiveness of CaP. The current study aims at the correlation of histopathologic findings of RARP specimens with pre-operative combined 68 Ga-PSMA PET/MRI imaging. Materials and Methods: Specimens retrieved after RARP in 38 patients of localised CaP were synchronised with pre-operative images obtained with simultaneous 68 Ga-PSMA PET/MRI. Maximum scores of individual parameters such as PI-RADS, Gleason’s score and PSMA uptake (in SUV) were taken for each sector and used for statistical analysis. Results: The positive predictive value (PPV) and negative predictive value (NPV) of simultaneous 68 Ga-PSMA PET and MRI in detecting malignancy were found to be 84.23% (95% CI: 80.74%–87.18%) and 63.92% (95% CI: 57.77%–69.65%), respectively. Combining 68 Ga-PSMA PET and mpMRI improves the sensitivity to 81.48% (95% CI: 76.70%–85.67%), but the specificity was found to be 68.24% (95% CI: 60.09%–75.64%). It was found that SUV max correlated with the severity of GS ( P value < .001). Conclusion: Prediction and localisation of histological malignancy in the prostate could be improved pre-operatively by adding 68 Ga-PSMA PET to mpMRI imaging. The SUV of abnormal uptake of 68 Ga-PSMA radiotracer is predictive of aggressiveness of tumour as reflected in the Gleason score.