Usefulness of urinary NMP22 to detect tumor recurrence of superficial bladder cancer after transurethral resection

Background In a prospective study we compared the usefulness of urinary nuclear matrix protein 22 (NMP22) with that of urine cytology and other urinary markers in the monitoring of superficial bladder cancer after transurethral resection (TURBT).Methods The subjects were 156 patients, comprising 99 patients with superficial bladder cancer in whom TURBT was planned (untreated group) and 57 patients without tumors in the bladder who had been followed up after TURBT (follow-up group).Results Among the 156 patients, who were monitored for 11–26 months (median, 21 months), recurrence was observed in 51 patients (33.0%). At the time of recurrence, the sensitivities of NMP22, basic fetoprotein (BFP), and bladder tumor antigen (BTA) tests, and urine cytology were 18.6%, 23.3%, 9.3%, and 7.0%, respectively. The factors affecting the sensitivity of NMP22 were tumor size and urinary WBC. The size of recurrent tumors was significantly smaller (P 0.05) than that of the initial tumors. Based on receiver operating characteristic (ROC) curves calculated from the data of patients with recurrence, the ideal cutoff values at recurrence were recommended to be 5.0U/ml for NMP22 and 6.0ng/ml for BFP. Using these cutoff values, the sensitivities of NMP22 and BFP were 48.8% and 44.2%, respectively.Conclusions Because the size of recurrent bladder tumors is usually smaller than that of the initial tumors, the cutoff values of urinary markers should be reduced to detect these tumors. We recommend 5.0U/ml as a cutoff value of NMP22 for detection of recurrence of bladder tumor.