[Clinical significance of prostatic exosomal protein and PSA in detecting prostate cancer with the PSA gray zone and PI-RADS-3 lesions].

Abstract

Objective: To explore the clinical value of prostatic exosomal protein (PSEP) and PSA in the diagnosis of PCa with PSA in the gray zone (4－10 μg/L) and Prostate Imaging Reporting and Data System category 3 (PI-RADS-3) lesions.

Methods: From 2019 to 2022, 211 patients with the PSA gray zone and PI-RADS-3 lesions underwent prostate multi-parameter MRI, prostate needle biopsy or transurethral resection/enucleation of the prostate. We collected the baseline urine samples from the patients, examined the content of PSEP in the urine by ELISA and evaluated the performance of PSEP and PSA in the diagnosis of PCa.

Results: Among the total number of patients, 57 were confirmed with PCa (the positive group) and the other 154 with benign prostate conditions (the negative group) by biopsy pathology. The free PSA level (fPSA), free to total PSA ratio (f/tPSA) and PSEP content were dramatically lower in the positive than in the negative group (all P< 0.01). Uni- and multivariate analyses showed f/tPSA and PSEP to be independent factors for predicting PCa with the PSA gray zone and PI-RADS-3 lesions, with the AUC values of 0.70 and 0.78, best cutoff values of 0.18 and 1.45 μg/L, sensitivity of 84.21% and 70.18%, and specificity of 58.44% and 77.27%, respectively (P< 0.01). The multivariate model with combined use of f/tPSA and PSEP (AUC: 0.82, best cutoff value: 0.31, sensitivity: 82.46%, specificity: 75.32%) outperformed either f/tPSA or PSEP alone in the diagnosis of PCa with the PSA gray zone and PI-RADS-3 lesions (P< 0.01, P = 0.04).

Conclusion: For patients with the PSA gray zone and PI-RADS-3 lesions, f/tPSA and PSEP are significant predictors of PCa. The multivariate model of PSEP combined with f/tPSA can replace f/tPSA in the detection of PCa to improve diagnostic performance and avoid unnecessary prostate biopsy.