Urinary dual-site proenkephalin (PENK) methylation testing for detection of high-grade or invasive recurrence during surveillance of non-muscle-invasive bladder cancer

Non-muscle-invasive bladder cancer (NMIBC) requires long-term surveillance, but cystoscopy is invasive and urine cytology has limited sensitivity. We evaluated the diagnostic performance of a urinary dual-site proenkephalin methylation (ds-me PENK ) test (EarlyTect Bladder Cancer Detection Plus) for detecting high-grade or invasive recurrence during NMIBC surveillance. This prospective longitudinal study included 82 patients with histopathologically confirmed NMIBC who underwent transurethral resection followed by cystoscopic surveillance. Serial urine samples were analysed using ds-me PENK testing, the nuclear matrix protein 22 (NMP22) assay, and urine cytology. The primary endpoint was diagnostic accuracy for histopathologically confirmed high-grade or invasive recurrence. During a median follow-up of 12.3 months, 22 patients experienced recurrence. The ds-me PENK test detected 9 of 11 high-grade/invasive recurrences (sensitivity, 81.8%; 95% CI, 48.2–97.7%) and 6 of 11 Ta low-grade recurrences (54.5%). Urinary methylation levels declined after resection and remained low through follow-up in recurrence-free patients, whereas levels remained persistently elevated in those who later recurred. Its negative predictive value (NPV) for high-grade/invasive recurrence was 96.4% (95% CI, 87.5–99.6%). Corresponding sensitivities were 45.5% and 30.0%, and NPVs were 91.5% and 90.9%, for NMP22 and urine cytology, respectively. The ds-me PENK test detected five of the six observed stage/grade progression events. Urinary ds-me PENK testing showed high NPV for high-grade/invasive recurrence during NMIBC surveillance. It may complement cystoscopy as a molecular rule-out adjunct, but larger multicentre studies are required before the test can be used to modify cystoscopic surveillance schedules.