Correlation between urine cytology results on the day after overnight continuous saline irrigation following transurethral resection of bladder tumor and bladder tumor recurrence

Purpose: To investigate the relationship between urine cytology results after overnight continuous saline irrigation (OCSI) following transurethral resection of bladder tumor (TURBT) and bladder tumor recurrence in non-muscle invasive bladder cancer (NMIBC). Materials and Methods: A retrospective study was conducted on patients diagnosed with NMIBC between 2016 and 2020 after undergoing TURBT at our hospital. All patients received OCSI following TURBT and had urine cytology test at postoperative 1 day. Urine cytology was classified into three groups: Negative, low-grade urothelial neoplasm (LGUN)+atypical urothelial cells (AUC), and suspicious for high-grade urothelial carcinoma (SHGUC)+high-grade urothelial carcinoma (HGUC). Recurrence-free survival (RFS) in each group was compared using the Kaplan-Meier method. Univariable and multivariable Cox regression analyses were performed to evaluate independent prognostic factors. Results: A total of 172 patients were included in this study. Based on urine cytology group (after OCSI), RFS did not reach the median value in the Negative group. In the LGUN+AUC group, the median RFS was 615.00 days. In the SHGUC+HGUC group, the median RFS was 377.00 days. In survival analysis, the Negative group had a longer RFS than the SHGUC+HGUC group (p=0.013). However, Cox regression analysis showed that SHGUC+HGUC was not an independent prognostic factor for recurrence. Conclusions: Urine cytology results after OCSI following TURBT in NMIBC were associated with bladder tumor recurrence. Specifically, SHGUC or HGUC in urine cytology after OCSI showed earlier recurrence than negative cases. However, further research is needed to accurately determine whether it is an independent prognostic factor.