Table 2.

Challenges and future directions for liquid biopsy biomarkers in prostate cancer recurrence detection.

Challenge	Impact on exosomal miRNAs	Impact on ctDNA	Future considerations
Standardization of detection	Lack of consensus on isolation and analysis methods	Variability in sequencing depth and detection cutoffs	Establishing universal protocols for clinical use
Sensitivity and specificity	High specificity but variability in expression across patients	Sensitive but affected by tumor shedding dynamics	Optimizing detection algorithms to improve reliability
Cost and accessibility	Requires specialized RNA sequencing techniques	NGS and digital PCR remain costly and resource-intensive	Cost-effective assays needed for widespread adoption
Validation in large cohorts	Small-scale studies with inconsistent results	Needs more prospective trials with long-term follow-up	Large, multi-center studies essential for clinical translation
Clinical utility	Promising for early recurrence detection, but requires further validation	Potentially useful for guiding targeted therapies and real-time monitoring	Integration with PSA and imaging may enhance decision-making

ctDNA = circulating tumor DNA, miRNAs = exosomal microRNAs, NGS = next-generation sequencing, PSA = prostate-specific antigen.