Prediction of Postoperative Intravesical Recurrence Using Urine DNA Monitoring in Nonmuscular‐Invasive Urothelial Bladder Cancer

Objectives Considering the high frequency of intravesical recurrence in bladder urothelial carcinoma (UBC), accurate non‐invasive biomarkers for recurrence prediction are needed for better management after transurethral surgery. This pilot study examined the usefulness of urine DNA for detecting and predicting intravesical recurrence in UBC. Methods Patients with primary nonmuscle‐invasive UBC were prospectively enrolled just after initial transurethral surgery. Genomic profiles were evaluated in resected specimens of the original tumor and in urine during follow‐up. Urine DNA, urine cytology, and cystoscopy were all evaluated at 3‐month intervals until 1 year postoperatively. Upon centrifuging urine samples into precipitation and supernatant fractions, we retrospectively evaluated urine DNA using a genomic panel established in our previous report. Results In the 19 patients enrolled, intravesical recurrent tumors were detected in six patients by cystoscopy. Urine DNA was positive in all of the recurrence cases before or at the time of cystoscopic or cytological detection, whereas urine cytology did not test positive before cystoscopic recurrence. Both urine precipitation and supernatant samples tested positive in 5 of 6 recurrence cases, indicating no obvious differences in the fraction used. Urine DNA was positive in 4 of the 13 nonrecurrence cases, among which three tested negative following Bacille Calmette‐Guerin therapy. Conclusions Urine DNA as screened by our genomic panel may be useful for predicting and detecting intravesical recurrence in UBC. The simultaneous evaluation of urine precipitation and supernatant may enhance the clinical utility of urine DNA during surveillance for intravesical recurrence in UBC patients.