TERT promoter C228T and C250T mutation detection combined with cytology in the diagnosis of urothelial carcinomas: a real-world cohort study in a Chinese population

Urothelial carcinoma (UC) is a malignancy of the urinary tract characterized by a high recurrence rate, imposing a substantial healthcare burden. Although cystoscopy and ureteroscopy remain the diagnostic gold standards, their invasive nature causes considerable discomfort during surveillance. Somatic mutations in the promoter region of the telomerase reverse transcriptase (TERT) gene are common events in UC and serve as promising noninvasive urinary biomarkers. This study aimed to evaluate the diagnostic utility of combining urinary TERT promoter mutation detection with cytology for UC diagnosis and surveillance, potentially serving as an indicator for cystoscopy application. In this prospective study, 414 samples were collected, including 307 clinical patients, 25 non-tumorous hematuria patients, and 81 healthy controls. Droplet digital PCR (ddPCR) was used to detect TERT promoter mutations (C228T, C250T) in urinary cell-free DNA (cfDNA), alongside conventional cytology for comparison and combination analysis. The sensitivity and specificity of TERT promoter mutation detection were 48.6% and 84.7%, respectively, whereas those of cytology were 36.8% and 96.6%, respectively. Combining TERT mutation detection with cytology significantly improved diagnostic performance (sensitivity = 70.8%, specificity = 81.4%, AUC = 0.868). The mutant allele fraction (MAF) of TERT promoter mutations in UC patients was significantly higher than that in controls and showed an increasing trend with disease severity. Urinary TERT promoter mutation detection, particularly when integrated with cytology, enhances the diagnostic sensitivity and overall accuracy for UC. The MAF of TERT promoter mutations correlated with disease severity, indicating potential clinical utility. This combined noninvasive assay may serve as a practical adjunct for UC diagnosis and surveillance, complementing conventional cystoscopy in clinical practice.