Voided urine cytology is a useful tool predicting non-muscle-invasive bladder cancer risk before surgery

To determine the accuracy of voided urinary cytology (VUC) in predicting of non-muscle-invasive bladder cancer (NMIBC) risk stratification before surgery.

We prospectively collected data from all patients diagnosed with bladder cancer in our institution over 2 years. We have analyzed VUC accuracy of positive and suspicious VUC in the detection of high-risk tumors and negative and atypical VUC in the detection of low-risk tumors. To test this accuracy, we assessed sensitivity, specificity, positive (PPV) and negative predictive values (NPV), diagnostic odds ratio (DOR), and generated ROC curves (receiver operating characteristic curve).

With 224 patients included, the positive VUC subcategory showed a specificity of 92.4% (95%CI: 83.2%-97.5%) and a PPV of 91.4 (95%CI: 81%-97.1%). DOR in this subgroup was 6.81. In the suspicious VUC, specificity was 90.9% (95%CI: 81.3%-96.6%), PPV was 88% (95%CI: 75.7%-95.5%) and DOR was 4.23. Combined analysis of positive and suspicious cytologies for detecting high-risk NMIBC showed a sensitivity of 65% (95%CI: 57.3%-73.2%) and a DOR of 9.51. Negative VUC showed high specificity in detecting low-risk (93.2% [95%CI: 87.9%-96.7%]) and a DOR of 6.90 (95%CI: 3.07-15.46). Atypical VUC was the least accurate and had rather low specificity and predictive values.

VUC appears to be a good, inexpensive and easily available method to determine risk stratification before surgery. This can be useful in daily practice to determine which patients should receive a single instillation of MMC and to prioritize patients more likely to have a high- risk tumor.