Purpose: The high risk of recurrence after transurethral resection of bladder tumor of nonmuscle invasive disease requires lifelong treatment and surveillance. Changes in DNA methylation are chemically stable, occur early during tumorigenesis, and can be quantified in bladder tumors and in cells shed into the urine. Some urine markers have been used to help detect bladder tumors; however, their use in longitudinal tumor recurrence surveillance has yet to be established.
Experimental design: We analyzed the DNA methylation levels of six markers in 368 urine sediment samples serially collected from 90 patients with noninvasive urothelial carcinoma (Tis, Ta, T1; grade low-high). The optimum marker combination was identified using logistic regression with 5-fold cross-validation, and validated in separate samples.
Results: A panel of three markers discriminated between patients with and without recurrence with the area under the curve of 0.90 [95% confidence interval (CI), 0.86-0.92] and 0.95 (95% CI, 0.90-1.00), sensitivity and specificity of 86%/89% (95% CI, 74%-99% and 81%-97%) and 80%/97% (95% CI, 60%-96% and 91%-100%) in the testing and validation sets, respectively. The three-marker DNA methylation test reliably predicted tumor recurrence in 80% of patients superior to cytology (35%) and cystoscopy (15%) while accurately forecasting no recurrence in 74% of patients that scored negative in the test.
Conclusions: Given their superior sensitivity and specificity in urine sediments, a combination of hyper- and hypomethylated markers may help avoid unnecessary invasive exams and reveal the importance of DNA methylation in bladder tumorigenesis.