Urinary pH and oncologic outcomes after bacillus calmette-guérin in non-muscle invasive bladder cancer: a retrospective cohort study.

INTRODUCTION

Urinary pH may influence intravesical Bacillus Calmette-Guérin (BCG) efficacy by modulating the local immune microenvironment. We evaluated baseline urinary pH as a continuous variable and its association with oncologic outcomes in BCG-treated non-muscle invasive bladder cancer (NMIBC).

METHODS

In this retrospective cohort, 248 NMIBC patients receiving adequate BCG therapy were analyzed. Recurrence-free survival (RFS) and progression-free survival (PFS) were assessed using Cox proportional hazards models. Given limited progression events, ridge (L2-penalized) multivariable regression was applied. Urinary pH was modeled per 1-unit increase and age per 10-year increment. Model discrimination was evaluated using Harrell's concordance index.

RESULTS

During follow-up, 43 patients (17.3%) developed recurrence and 28 (11.3%) experienced progression. In multivariable analysis, urinary pH was independently associated with improved RFS (HR 0.53, 95% CI 0.29-0.96, p = 0.035). For PFS, urinary pH showed a similar inverse direction but borderline significance after ridge adjustment (HR 0.69, 95% CI 0.48-1.00, p = 0.052). Concomitant carcinoma in situ and tumor stage remained independent predictors of progression. Model discrimination was good for RFS (C-index 0.713) and strong for PFS (C-index 0.841).

CONCLUSIONS

Baseline urinary pH demonstrated an independent association with recurrence and a consistent directional association with progression in BCG-treated NMIBC. While dominant pathological features primarily determine progression risk, urinary pH may represent an accessible microenvironmental modifier of BCG responsiveness. Prospective validation is warranted.