Impact of Urinary pH on the Efficacy of a Postoperative Single Instillation of Mitomycin-C

Abstract

Objective: To assess the effect of the urinary pH value on the efficacy of a postoperative single instillation of mitomycin-C. Study Design: A descriptive study. Place and Duration of Study: Department of Urology, Ankara Numune Training and Research Hospital, Ankara, Turkey from 2011 to 2016. Methodology: Patients newly diagnosed with low-risk non-muscle invasive bladder cancer and given a postoperative single instillation of mitomycin-C were retrospectively reviewed. The demographic data and pre-instillation urinary pH values of the patients were recorded. All patients included in the study (n=117) were followed up for five years. The primary outcome was the time to the first recurrence. The patients were divided into two groups: Group 1 consisted of 87 patients with no recurrence and Group 2 comprised 30 patients that had recurrence during the follow-up. Results: The mean pre-instillation urinary pH value was significantly lower in Group 2 than in Group 1 (5.89 vs. 5.37, p <0.001). The receiver operating characteristic analysis revealed that the cut-off value of urinary pH in predicting recurrence was 5.25. The patients with a urinary pH value of 5.25 or greater had significantly higher recurrence-free survival rates. Conclusions: The patients with higher urinary pH before a single instillation of mitomycin-C had better recurrence-free survival.