#0420

Evaluating the Performance of Cxbladder Triage and Detect and Imaging for the Detection of Urothelial Cancer in Patients with Gross Hematuria: A Canterbury, New Zealand Audit

G. Losco^1,2, T. Aboushwareb³

¹University of Otago, Department of Surgery, Christchurch, New Zealand
²Health NZ Te Whatu Ora Waitaha Canterbury, Department of Urology, Christchurch, New Zealand
³Pacific Edge Diagnostics USA Limited, Hummelstown, United States

Introduction:

Gross hematuria (GH) is a key indicator of potential underlying urothelial carcinoma (UC). In the Canterbury region of New Zealand, Cxbladder Triage and imaging (CT-IVU unless contraindicated due to allergy or low GFR then US) have been used to inform the decision to refer patients for evaluation of GH. The Cxbladder Triage test-negative rate (TNR; indicating low UC risk) for GH patients is low and suboptimal, while the TNR in microhematuria patients is acceptable (64%). This study audited the first 500 GH patients undergoing hematuria evaluation in 2024 in Canterbury, New Zealand, and compared the diagnostic performance of Cxbladder Triage (CxbT) or Cxbladder Detect (CxbD) with imaging modalities to assess their sensitivity and specificity in detecting UC.

Material and methods:

A retrospective analysis was conducted using data from 500 patients with frequent GH who underwent both imaging and Cxbladder testing. Gold standard pathology confirmation of UC was applied. Sensitivity (Sn), specificity (Sp), negative predictive value (NPV), positive predictive value (PPV), and TNR were calculated for CxbD, CxbT, imaging (CT-IVU unless contraindicated due to allergy or low GFR then US), and their combination.

Results:

Of 500 GH patients, 39 (8%) had a confirmed diagnosis of UC. One case was excluded due to a misclassification of endometrioid adenocarcinoma. CxbT alone had a Sn of 100%, Sp of 29%, NPV of 100%, PPV of 11%, and TNR of 27% (Table). The diagnostic performance was similar when CxbT was combined with imaging. CxbD alone had a Sn of 85%, Sp of 68%, NPV of 98%, PPV of 18%, and TNR of 64%. When combined with imaging, the Sn of CxbD increased to 97%, while the Sp, NPV, and TNR were similar (the false negative was < 1 mm High Grade pTa). The number of false negatives (missed tumors) was lower with CxbT or CxbD (alone or combined with imaging) when compared with imaging alone. Imaging alone had a Sn of 71%, Sp of 97%, NPV of 98%, PPV of 69%, and TNR of 92%.