Impact of clinical factors, including a point-of-care nuclear matrix protein-22 assay and cytology, on bladder cancer detection

Abstract

Objective: To determine whether the nuclear matrix protein-22 (NMP22) assay can improve the accuracy of discriminating between high-risk patients with and without bladder cancer.

Patients and methods: Age, gender, race, smoking status, haematuria and its extent, and the NMP22 and urinary cytology results, were available for 1272 patients. The data of 670 (52.7%) from four study sites were used to develop a logistic regression model-based nomogram to predict the presence of bladder cancer. The remaining data from 602 (47.3%) patients from nine study sites were used to externally validate the nomogram. A separate nomogram was developed for urinary cytology, and for the combination of NMP22 and urinary cytology findings.

Results: Of 1272 patients, 76 (6.0%) had bladder cancer, 217 (17.1%) were NMP22-positive and 17 (1.3%) had malignant cells on urinary cytology. NMP22 and urinary cytology results were independent predictors of bladder cancer (P = 0.005 and 0.007, respectively). In external validation, the area under the curve (AUC) for NMP22 was 76.0% vs 56.2% for cytology. External validation of the multivariable NMP22-based bladder cancer nomogram gave an AUC of 82.4% vs 74.7% for the multivariable cytology-based nomogram (gain 7.7%; P = 0.006) vs 82.6% for the multivariable nomogram combining NMP22 and cytology results (gain 0.2%; P = 0.1).

Conclusions: The ability of the NMP22 test to predict bladder cancer in high-risk patients significantly exceeds that of urinary cytology. The NMP22-based nomogram can help to identify individuals at risk of bladder cancer.