PD58-04: A Comprehensive Liquid Biopsy to Detect Primary Upper Tract Urothelial Carcinoma: A Pilot Study

Alireza Ghoreifi*, Stephanie Shishido, Jeremy Mason, George Courcoubetis, Manju Aron, Inderbir Gill, Monish Aron, Mihir Desai, Siamak Daneshmand, Peter Kuhn, Hooman Djaladat, Los Angeles, CA

Introduction: Diagnosis and preoperative risk stratification of patients with upper tract urothelial carcinoma (UTUC) present distinct challenges given the limitations of current available diagnostic tools, such as imaging and endoscopic biopsy. Blood-based liquid biopsy has emerged as a novel diagnostic and prognostic biomarker in cancer patients, yet the possibility of this test in UTUC patients is unknown. The aim of this study is to explore the feasibility of a liquid biopsy to detect UTUC.

Methods: Under an IRB-approved protocol, blood samples were collected from primary UTUC patients before radical nephroureterectomy between May and October 2021. Patients with concomitant bladder cancer or those with positive bladder biopsies within the past 3 months were excluded. The samples were analyzed using third generation of comprehensive high-definition single cell assay (HDSCA3.0) to detect single cell circulatory tumor cells (CTCs). The findings were compared to the blood samples of normal blood donors (NBDs) who had no known pathology.

Results: A total of 5 UTUC patients and 5 NBDs were included in the pilot analysis. Demographic and pathological features of the UTUC patients are shown in Table 1. All patients showed papillary UTUC with no variant histology. HDSCA3.0 analysis indicated that rare cells are detectable in the peripheral blood collected from UTUC patients with high heterogeneity (Figure 1-A). The total rare cell count detected in UTUC patient samples was significantly higher than that from the NBDs (p-value = 0.009). Similar trend was seen in total CK+ cells (p=0.009), DAPI|CK (p=0.009), DAPI|Vim (0.028), DAPI|CK|Vim|CD45/CD31 (p=0.009), and DAPI only (p=0.009) (Figure 1-B).

Conclusions: In this pilot study, the proposed liquid biopsy is feasible in UTUC patients. UTUC samples showed significantly higher rare cell count compared to the normal blood donors. A larger sample size study, including follow-up blood samples, to validate the accuracy of this test is the next step.

Source of Funding: USC Urology Pilot Research Program