Diagnostic performance and predictive capacity of early urine cytology after transurethral resection of nonmuscle invasive bladder cancer: A prospective study.

OBJECTIVES

To prospectively evaluate the value of early urine cytology (EUC) after the primary transurethral resection of bladder tumor (TURBT) of nonmuscle invasive bladder cancer (NMIBC) for the prediction of positive biopsy findings on repeat TURBT.

METHODS

After approval of institutional review board, patients who underwent TURBT for NMIBC between February 2014 and July 2018 were included in the study. Patients with concomitant Carcinoma in Situ (CIS), upper tract urothelial tumors, biopsy proven muscle invasion, or low-risk NMIBC (single, primary, Ta, and G1 tumor) were excluded. Forty-eight hours after primary TURBT, EUC was retrieved and patients were scheduled for repeat TURBT 2 to 6 weeks later according to the predetermined protocol. The primary outcome was to determine the role of positive EUC to predict positive biopsy findings on repeat TURBT.

RESULTS

During the study period, 198 patients fulfilled the study inclusion criteria of which 49 (25%) had recurrent NMIBC. Primary TURBT pathology results showed T1 stage in 195 (98.5%) patients and high-grade malignancy in 158 (79.8%). Intermediate- and high-risk NMIBC were defined in 49 (25%) and 149 (75%) patients, respectively. EUC was positive in 114 patients; of whom 78 (68.4%) showed positive biopsy findings on repeat TURBT (P = 0.001). The sensitivity, specificity, negative, and positive predictive values of EUC for biopsy findings at repeat TURBT were 90% (95%CI: 87-94), 75% (95%CI: 71-79), 89% (95%CI: 85-94), and 68% (95%CI: 62-74), respectively. On mean (±SD) follow-up of 42(±13) months, tumor recurrence was encountered in 101 (53%) patients. On multivariate Cox regression analysis, EUC was significantly associated with tumor recurrence (HR = 4.6, 95%CI: 2.37-8.9, P < 0.001).

CONCLUSIONS

Positive EUC after primary TURBT for NMIBC is significantly associated with positive repeat TURBT for malignancy. EUC is an independent predictor of tumor recurrence. EUC might be implemented after primary TURBT to help refining indications of repeat biopsy and planning of further intervention.