Blood Extracellular Vesicles Beyond Circulating Tumour Cells: A Valuable Risk Stratification Biomarker in High-Risk Non-Muscle-Invasive Bladder Cancer Patients

Non-muscle-invasive bladder cancer (NMIBC) prognosis varies significantly due to the biological and clinical heterogeneity. High-risk stage T1-G3, comprising 15-20% of NMIBCs, involves the lamina propria and is associated with higher rates of recurrence, progression, and cancer-specific mortality. In the present study, we have evaluated the enumeration of tumour-derived extracellular vesicles (tdEVs) and circulating tumour cells (CTCs) in high-risk NMIBC patients and their correlation with survival outcomes such as time to progression (TTP), and cancer-specific survival (CSS). Eighty-three high-risk T1-G3 NMIBC patients treated between September 2010 and January 2013 were included. Blood samples were collected before a transurethral resection of the bladder (TURB) and analysed using the CellSearch^® system. The presence of at least one CTC was associated with a shorter TTP and CSS. Extending follow-up to 120 months and incorporating automated tdEV evaluation using ACCEPT software demonstrated that tdEV count may additionally stratify patient risk. Combining tdEVs and CTCs improves risk stratification for NMIBC progression, suggesting that tdEVs could be valuable biomarkers for prognosis and disease monitoring. Further research is needed to confirm these findings and establish the clinical significance of tdEVs in early-stage cancers.