Continuous saline bladder irrigation for two hours following transurethral resection of bladder tumors in patients with non-muscle invasive bladder cancer does not prevent recurrence or progression compared with intravesical Mitomycin-C

BACKGROUND: Intravesical Mitomycin-C (MMC) following transurethral resection of bladder tumor (TURBT), while efficacious, is associated with side effects and poor utilization. Continuous saline bladder irrigation (CSBI) has been examined as an alternative. In this study we sought to compare the rates of recurrence and/or progression in patients with NMIBC who were treated with either MMC or CSBI after TURBT. METHODS: We retrospectively reviewed records of patients with NMIBC at our institution in 2012–2015. Perioperative use of MMC (40 mg in 20 mL), CSBI (two hours), or neither were recorded. Primary outcome was time to recurrence or progression. Descriptive statistics, chi-squared analysis, Kaplan-Meier survival analysis, and Cox multivariable regression analyses were performed. RESULTS: 205 patients met inclusion criteria. Forty-five (22.0%) patients received CSBI, 71 (34.6%) received MMC, and 89 (43.4%) received no perioperative therapy. On survival analysis, MMC was associated with improved DFS compared with CSBI (p = 0.001) and no treatment (p = 0.0009). On multivariable analysis, high risk disease was associated with increased risk of recurrence or progression (HR 2.77, 95% CI: 1.28–6.01), whereas adjuvant therapy (HR 0.35, 95% CI: 0.20–0.59) and MMC (HR 0.43, 95% CI: 0.25–0.75) were associated with decreased risk. CONCLUSIONS: Postoperative MMC was associated with improved DFS compared with CSBI and no treatment. The DFS benefit seen with CSBI in other studies may be limited to patients receiving prolonged irrigation. New intravesical agents being evaluated may consider saline as a control given our data demonstrating that short-term CSBI is not superior to TURBT alone.