Use of the nuclear matrix protein 22 Bladder Chek test™ in the diagnosis of residual urothelial cancer before a second transurethral resection of bladder cancer
OBJECTIVES To assess the efficacy of nuclear matrix protein 22 (NMP-22) in the diagnosis of recurrent, superficial bladder cancer and whether it can predict for future recurrence. METHODS Patients with diagnosed and treated superficial transitional cell carcinoma urinary bladder (Stage Ta, T1, Tis, Nx, and M0) presenting for surveillance follow-up were prospectively enrolled in this study from February 2004 to August 2005. These patients underwent urine cytology, NMP-22 testing, and cystopanendoscopy on enrollment in the study. For the next year, these patients underwent cystopanendoscopy and cytology at 3-month intervals. The ability of NMP-22 to predict for recurrence was determined using the cystoscopy findings as the reference standard. RESULTS A total of 145 patients were included in the study. Of these, 56 had recurrence at enrollment. Of the 56 patients, 48 had positive NMP-22 findings and 22 had positive urine cytology findings. The sensitivity, specificity, positive predictive value, and negative predictive value was 85.7%, 77.5%, 70.6%, and 89.6%, respectively, for NMP-22 alone and 92.9%, 75.3%, 70.3%, and 94.4%, respectively, when the cytology and NMP-22 findings were combined. During the subsequent follow-up of 1 year, 61 recurrences developed in 47 patients. Cox regression analysis showed that those with positive NMP-22 had a 9.57 times greater risk of recurrence during 1 year compared with those with negative NMP-22. CONCLUSIONS The results of our study have shown that the addition of NMP-22 testing to cytology increases the sensitivity for recurrence detection in patients with superficial transitional cell bladder cancer. Patients with positive NMP-22 findings developed significantly more recurrences compared with those with negative NMP-22 findings.