Introduction: The objective of this study is to evaluate the efficacy of a PENK methylation test in detecting recurrent non-muscle invasive bladder cancer (NMIBC) and to compare its performance to that of NMP22 and cytology in a prospective pilot study. Methods: A total of 188 patients with a history of NMIBC and scheduled for cystoscopy surveillance after TURBT were enrolled in the study. Urine samples were collected and analyzed using the Linear Target Enrichment (LTE)-quantitative methylation-specific real-time PCR (qMSP) test (mePENK-LTE-qMSP) for measuring PENK methylation, as well as the NMP22 test. The reference standard for NMIBC was cystoscopy and pathology. The mePENK-LTE-qMSP test was conducted with a cut-off value determined by ROC analysis of 32.0, and results were classified as positive or negative. The cystoscopy results were classified as recurrence or non-recurrence, and recurrences were further subcategorized as progression or non-progression. The clinical performance of the mePENK-LTE-qMSP test was analyzed and compared to NMP22 and cytology. Results: The mePENK-LTE-qMSP test had a sensitivity of 78.4% (40/51) and a specificity of 85.0% (108/127) in detecting NMIBC. It had higher sensitivity than NMP22 (P = 0.0106) or cytology (P < 0.001), while its specificity was not significantly different from NMP22 (P = 0.6076) but inferior to cytology (P = 0.0001). Subgroup analysis demonstrated that the mePENK-LTE-qMSP test had a sensitivity of 46.7% (7/15) and a specificity of 96.6% (28/29) in detecting NMIBC among low- and intermediate-risk patients. It also had a sensitivity of 91.2% (31/34) and a specificity of 81.0% (68/84) in detecting NMIBC among high-risk patients. Patients who were recurrence-free at the time of diagnosis had follow-up cystoscopy, at a median follow-up duration of 223 days (n=71). The mePENK test positive patients (n=14) had a significantly shorter recurrence-free survival than test-negative patients (n=57) (245 days vs 503 days, hazard ratio = 9.4 (95%CI 2.4 to 35.9), p < 0.0001). Conclusions: The mePENK-LTE-qMSP test demonstrated high sensitivity and specificity in detecting recurrent NMIBC and accurately excluded non-recurring or non-progressing NMIBC during surveillance. Additionally, it was able to predict NMIBC recurrence before recognition by cystoscopy. SOURCE OF Funding: Genomictree, Inc. of South Korea sponsored this study.
