Impact of age on outcomes of patients with non muscle-invasive bladder cancer treated with immediate postoperative instillation of mitomycin C

Objectives: To evaluate whether age affects the clinical benefit afforded by immediate postoperative intravesical instillation of mitomycin C in a contemporary cohort of patients with NMIBC. Patients and methods: A total of 4,258 patients with NMIBC treated with transurethral resection of the bladder with (n = 2,605, 61%) or without (n = 1,652, 39%) one immediate instillation of mitomycin C from 5 institutions (study period: 2000-2007) were included. No patients received adjuvant instillations. A multivariable Cox proportional hazards regression model adjusting for standard clinical and pathological features tested the potential interaction term between age and administration of mitomycin C with regard to disease recurrence. Results: A total of 2,063 patients experienced disease recurrence with a median follow-up of 48 months for those who did not recur. In multivariable Cox regression analysis, immediate postoperative instillation of mitomycin C (HR: 0.62; 95% CI: 0.56-0.68; P < 0.0001) and age (HR: 1.04; 95% CI: 1.00-1.09; P = 0.036) were associated with disease recurrence. We observed only slight decreases in recurrence-free survival with age irrespective of treatment administration of mitomycin C or not. Conclusion: We confirmed reduced disease recurrence rates associated with 1 immediate postoperative intravesical instillation of mitomycin C in NMIBC patients. The benefit on recurrence -free survival of a postoperative intravesical instillation was preserved across all ages and therefore age by itself should not be taken into consideration when deciding to use it. (c) 2018 Elsevier Inc. All rights reserved.