Transrectal ultrasonographic parameters combined with total serum exosomes for the assessment of bone metastases in prostate cancer.

This study investigated transrectal ultrasound parameters and total serum exosome levels in prostate cancer (PCa) patients with bone metastasis (BM), and evaluated their combined value in assessing metastatic status. 40 PCa patients were categorized into non-bone metastasis (NBM, 21 cases) and BM (19 cases) groups based on single photon emission computed tomography/computed tomography or bone scans. Serum exosomes were extracted and analyzed via nanoparticle tracking analysis, while transrectal ultrasound and ultrasound-guided biopsies were performed. The study compared exosome levels and ultrasound parameters between groups, and assessed their diagnostic value for BM using receiver operating characteristic (ROC) curves, and analyzed correlations between exosomes and ultrasound findings. PCa patients with BM showed significantly higher serum exosome concentrations and ultrasound parameters (peak intensity, area under the curve (AUC), and Grad) than NBM patients (p < 0.001). ROC analysis revealed optimal cutoff values for discriminating BM: 19.33 dB for PI, 1,156.63 dB s for AUC, 2.02 dB/s for Grad, and 3.34 × E10 particles/mL for exosomes. The combined test (AUC = 0.97) outperformed individual parameters (AUCs 0.83-0.89), demonstrating superior diagnostic performance in identifying PCa BM. In conclusion, this exploratory preliminary study indicates that exosomes may have potential application value in the assessment of PCa BM.