Diagnostic performance of 68Ga-PSMA PET/CT for identification of aggressive cribriform morphology in prostate cancer with whole-mount sections

PurposeTo explore the diagnostic performance of Ga-68-PSMA PET/CT for identification of pathological cribriform morphology in prostate cancer (PCa).MethodsThe study retrospectively enrolled 49 PCa patients who had undergone preoperative multiparametric MRI (mpMRI) and Ga-68-PSMA PET/CT, and who had Gleason pattern (GP) 4 and absence of GP 5 on radical prostatectomy specimens. Lesions with GP 4 were outlined and stratified according to their cribriform status. Volumes of interest were drawn on matched mpMRI and PET images, and parameters including average apparent diffusion coefficient (ADC(mean)), tenth percentile ADC (ADC(10%)) and maximum standardized uptake value (SUVmax) were derived. The Mann-Whitney U test was used for continuous variables and the chi-squared test for categorical variables. Receiver operating characteristic analysis was used to compare imaging parameters in identifying cribriform morphology. The associations between cribriform-positive PCa and imaging variables were evaluated in a univariate analysis using a logistic regression model.ResultsA total of 62 lesions were identified in 49 patients with GP 4. Of these lesions, 37 (59.7%) in 34 patients (69.4%) showed cribriform morphology. ADC(mean) and ADC(10%) were similar between cribriform-positive and non-cribriform groups (P>0.05), while SUVmax was significantly different (median SUVmax 18.3 vs. 9.4 per patient, P=0.003, 18.2 vs. 7.2 per lesion, P<0.001), yielding sensitivities and specificities of 76% and 86% in a per-patient analysis, and 77% and 88% in a per-lesion analysis, respectively. Further, PSMA was significantly overexpressed in cribriform-positive PCa (P=0.003). SUVmax was a significant predictor of cribriform morphology in PCa (odds ratio 8.61, 95% confidence interval 4.96-25.27, per patient; odds ratio 11.93, 95% confidence interval 6.49-33.74, per lesion; both P<0.001).Conclusion(68)Ga-PSMA PET/CT effectively identifies the aggressive cribriform morphology in PCa.