Comparison of DNA methylation and cytology tests in urine to detect upper tract urothelial carcinoma: A paired-design diagnostic study

Abstract Objectives To evaluate the diagnostic efficacy of a DNA methylation test, compare that test with cytology alone, fluorescence in situ hybridization (FISH) alone, and cytology plus FISH, and explore reasons that may influence the accuracy of liquid biopsy. Methods We included 37 patients and 12 negative control individuals between April 2019 and May 2022. All patients had undergone radical nephroureterectomy, nephrectomy, diagnostic ureteroscopy, or tissue biopsy. Urine samples were collected for DNA methylation testing, cytology, and FISH. Test performance was calculated, and receiver operating characteristic curves were drawn for comparison. Results Median patient age was 66 years, and κ = 0.576 (P < .001) for the DNA methylation test and tissue pathology. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the DNA methylation test were 76%, 100%, 100%, and 74%, respectively, compared with 31%, 100%, 100%, and 50%, respectively, for cytology. The sensitivity, specificity, PPV, and NPV of cytology plus FISH were 66%, 100%, 100%, and 67%, respectively. The area under the curve (AUC) of the DNA methylation test was 0.879 (P < .001), and the AUC of cytology plus FISH was 0.828 (P < .001). Conclusions The test performance of DNA methylation was satisfactory. The DNA methylation test for the detection of upper tract urothelial carcinoma demonstrated better sensitivity than did cytology alone or cytology with FISH, but the accuracy of the combined tests was still acceptable. Further prospective studies with larger samples are needed to confirm the clinical value of this promising method.