Recurrence Rate After Post-Operative Two-Hour Continuous Bladder Irrigation for Primary Non-Muscle-Invasive Bladder Cancer: A Retrospective Cohort Study

Background: High recurrence rates for non-muscle-invasive bladder cancer (NMIBC) remain a clinical challenge. Recommended post-operative treatments are underutilized, highlighting the need for alternative strategies. Given the variability in bladder cancer prognosis, personalized treatment approaches are highly relevant. In this study, we evaluated post-operative two-hour continuous sterile water bladder irrigation (CSWBI) regarding recurrence and safety, as a potential addition to the treatment arsenal for bladder cancer. Method: In 2018, two-hour CSWBI was implemented as routine treatment after all transurethral resection procedures of the bladder (TURB), at the urology department of Sundsvall Hospital. All patients who underwent TURBs four years prior (control group) and four years after the implementation of CSWBI (intervention group) were analyzed. Primary NMIBC were included, MIBC and CIS were excluded. Data were collected retrospectively from patient records, including baseline characteristics, adverse events, and recurrence rates within 12 months follow-up. Statistical analyses included Chi-squared test, Wilcoxon rank-sum test, univariate and multivariate logistic regression analyses, Kaplan–Meier curves and log-rank test. Results: A total of 168 patients were included (control group n = 90, irrigation group n = 78). Median age was 73 years, 23% were female, 77% were male, and 74% were active or previous smokers. The recurrence rate within twelve months for the intervention group vs. the control group was: 27% vs. 21% (p = 0.4) respectively. CSWBI had no statistically significant impact on recurrence (OR 1.25, 95% CI 0.58–2.68, p = 0.6). Adverse effects were limited and equal between groups. Conclusions: Post-operative two-hour CSWBI did not significantly reduce NMIBC recurrence within twelve months in this cohort.