Characterization of Cellular and Acellular Analytes from Pre-Cystectomy Liquid Biopsies in Patients Newly Diagnosed with Primary Bladder Cancer.

Abstract

Simple SummaryThe standard of care for patients diagnosed with localized bladder cancer (BCa) is cystectomy. However, emerging evidence shows that the patients receiving surgical intervention often experience a return of their cancer. Examining patient blood samples for rare events, such as circulating tumor cells (CTCs) and large extracellular vesicles (LEVs), may reveal biomarkers indicative of the presence of cancer and provide an insight into disease progression. Through computational methodologies, each event in the blood was characterized to determine its rarity within the sample and then compared to events found in normal donors. We demonstrate that a wide range of CTCs and LEVs are found in significantly higher proportions among BCa patients compared to normal donors. This result suggests that the blood liquid biopsy is a proficient analyte for detecting BCa to ultimately guide clinical decisions to improve patient treatment outcomes.Urinary bladder cancer (BCa) is the 10th most frequent cancer in the world, most commonly found among the elderly population, and becomes highly lethal once cells have spread from the primary tumor to surrounding tissues and distant organs. Cystectomy, alone or with other treatments, is used to treat most BCa patients, as it offers the best chance of cure. However, even with curative intent, 29% of patients experience relapse of the cancer, 50% of which occur within the first year of surgery. This study aims to use the liquid biopsy to noninvasively detect disease and discover prognostic markers for disease progression. Using the third generation high-definition single cell assay (HDSCA3.0), 50 bladder cancer patient samples and 50 normal donor (ND) samples were analyzed for circulating rare events in the peripheral blood (PB), including circulating tumor cells (CTCs) and large extracellular vesicles (LEVs). Here, we show that (i) CTCs and LEVs are detected in the PB of BCa patients prior to cystectomy, (ii) there is a high heterogeneity of CTCs, and (iii) liquid biopsy analytes correlate with clinical data elements. We observed a significant difference in the incidence of rare cells and LEVs between BCa and ND samples (median of 74.61 cells/mL and 30.91 LEVs/mL vs. 34.46 cells/mL and 3.34 LEVs/mL, respectively). Furthermore, using classification models for the liquid biopsy data, we achieved a sensitivity of 78% and specificity of 92% for the identification of BCa patient samples. Taken together, these data support the clinical utility of the liquid biopsy in detecting BCa, as well as the potential for predicting cancer recurrence and survival post-cystectomy to better inform treatment decisions in BCa care.