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

Purpose: To explore the diagnostic performance of ⁶⁸Ga-PSMA PET/CT for identification of pathological cribriform morphology in prostate cancer (PCa).

Methods: The study retrospectively enrolled 49 PCa patients who had undergone preoperative multiparametric MRI (mpMRI) and ⁶⁸Ga-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 (SUV_max) 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.

Results: A 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 SUV_max was significantly different (median SUV_max 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). SUV_max 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: ⁶⁸Ga-PSMA PET/CT effectively identifies the aggressive cribriform morphology in PCa.