Diagnostic Accuracy of Urinary Cytology, and Deoxyribonucleic Acid Flow Cytometry and Cytology on Bladder Washings During Followup for Bladder Tumors

Abstract

Purpose We evaluated the diagnostic accuracy of cytology on urine and bladder washings, and deoxyribonucleic acid (DNA) flow cytometry on bladder washings compared to cystoscopy during followup for bladder tumors. Materials and Methods A cross-sectional analysis was performed on 166 patients with a history of bladder tumor for the initial visit when cytology and DNA flow cytometry results were available for urine and bladder washing samples. There were 114 bladder tumor events and 52 negative controls (normal cystoscopy). A prospective study was conducted among the 66 patients with no tumor detected by cystoscopy at the initial visit and for whom the 3 test results were available. The patients were followed from this visit until tumor recurrence or the end of the followup period. Cytological examination was considered positive only when interpreted as malignant. Suspicious examinations were considered negative for the purpose of our study. Results Sensitivity and specificity of urinary cytology were 59 and 85%, respectively. Sensitivity was increased to 66% using bladder washing cytology whereas specificity was moderately decreased to 83%. The sensitivity and specificity of DNA aneuploidy were 45 and 87%, respectively. Inclusion within the aneuploid category of hyperdiploid samples (defined as more than 7% of cells in the S + G2M phase) increased sensitivity to 77%, while specificity decreased to 42%. Kaplan-Meier analysis of tumor-free survival in patients initially free of bladder cancer at cystoscopy showed an inability of DNA flow cytometry to predict recurrence, whereas positive urine or bladder washing cytology predicted a shorter time to recurrence (log-rank test p <0.01). Conclusions These results show that DNA flow cytometry and cytology on bladder washing samples add little information to that obtained from voided urine cytology.