Introduction:

Upper tract urothelial carcinoma (UTUC) is an uncommon, yet lethal tumor of the urinary tract. Diagnosis and preoperative risk stratification of these patients present distinct challenges given the limitations of current available diagnostic tools such as urine cytology, endoscopic biopsy, and cross-sectional imaging. Herein, we explore the feasibility of a urine-based epigenetic assay to detect UTUC. 

Methods:

Under an IRB-approved protocol, urine samples were collected from UTUC patients before radical nephroureterectomy (RNU)/ureteroscopy (URS) between December 2019 and July 2021. Patients with concomitant bladder cancer and those who did not pass the quality control due to low DNA concentration (n=5) were excluded. The findings were compared to 64 sex/age-matched cancer-free healthy individuals (controls). Samples were analyzed with Bladder CARE™, a urine-based assay that measures methylation levels of 3 cancer biomarkers (TRNA-Cys, SIM2, and NKX1-1) and two internal control loci using methylation-sensitive restriction enzymes coupled with qPCR. Results are reported as Bladder CARE Index (BCI) score and quantitatively categorized as positive (BCI > 5), high-risk (BCI 2.5-5), or negative (BCI < 2.5). 

Results:

A total of 33 patients (29 RNU and 4 URS) with a median (range) age of 75 (45-88) years were included in the final analysis. All patients who underwent URS were confirmed to have UTUC through biopsy. Final pathology of patients who underwent RNU revealed stage Ta (n=12), T1 (n=4), T2 (n=5), T3 (n=7), and T4 (n=1) UTUC. All samples showed positive BCI results. Urine cytology was available in 21 patients of which 7 were false negative (33%). UTUC patients had significantly higher BCI values compared to the controls (mean BCI 199.1 vs. 1.7, respectively; p < 0.0001) (Figure 1-A). The Receiver Operating Characteristic (ROC) curve showed sensitivity, specificity, positive predictive value, and negative predictive value of 100%, 86%, 76%, and 100%, respectively (AUC = 0.9995) (Fig. 1B). 

Conclusion:

In this pilot study, the proposed urine-based epigenetic assay showed high sensitivity and negative predictive value in the diagnosis of patients with UTUC. A larger sample size study to validate the accuracy of this test is the next step.

Funding: Zymo Research Corp, Pangea Laboratory