Objectives: To compare the diagnostic value of two enzyme-linked immunosorbent assay (ELISA) tests, the nuclear matrix protein 22 (NMP22) test and a newly developed urinary bladder cancer (UBC) test, in patients having symptoms suggestive of urothelial cell carcinoma (UCC) and patients under follow-up after transurethral resection (TUR).
Methods: Two hundred forty patients with a mean age of 65.8 years (range 22 to 92) were included in this retrospective study. The tests were performed on previously frozen urine samples. Eighty-one patients had symptoms suggestive of bladder cancer and 159 patients were being followed up after complete TUR of UCC. Voided urine was evaluated by the NMP22 test and the monoclonal UBC-ELISA test, which traces cytokeratins 8 and 18. All patients underwent subsequent cystoscopy and biopsy evaluation of any suspicious lesion. The cutoff levels for bladder cancer positivity were 10 U/mL for the NMP22 test and 12 microg/L for the UBC test.
Results: In the 54 patients with histologically proved UCC, the NMP22 test had a sensitivity of 55.5% and the UBC test a sensitivity of 64.8%. According to the histologic stages, the sensitivity of NMP22 was 51.7% in pTa tumors, 46.1% in pT1, and 70% in pT2 or higher tumors; the sensitivity of UBC was 62.1% in pTa, 53.8% in pT1, and 80% in pT2 or higher tumors. For histologic grades 1 to 3, the sensitivity was 50%, 50%, and 68.7% for NMP22 and 66.6%, 60%, and 68.7% for UBC, respectively. The specificity was 79% and 92% for NMP22 and UBC, respectively.
Conclusions: The monoclonal UBC-ELISA test is superior to the NMP22 test in both sensitivity and specificity. Nevertheless, neither test can replace cystoscopy.