Prognostic value of inflammation or granuloma after intravesival BCG in non-muscle-invasive bladder cancer

Abstract

Objective: To evaluate the prognostic value of inflammation or granuloma after intravesical bacille Calmette-Guérin (BCG) treatment in non-muscle-invasive bladder cancer (NMIBC).

Materials and methods: Patients with NMIBC treated with intravesical BCG over a 5-year period were identified. The correlations between histopathological results and disease recurrence and progression were assessed, with survival analysis performed using the Kaplan-Meier method. Other relevant variables were also evaluated using univariate and multivariate analysis. A log-rank test was performed to compare time-to-event between groups.

Results: A total of 215 patients were treated with BCG for NMIBC and the median follow-up was 32 months. Granuloma was identified in 60 patients and inflammation in 125 patients. In 18 patients there was no evidence of either (normal histology group). A total of 12 patients did not have biopsies and were subsequently excluded. The mean recurrence-free survival rate was significantly higher in the granuloma and inflammation groups (65 months [95% CI: 58-72] and 56 months [95% CI: 49-63], respectively) than in the normal histology group (20 months [95% CI: 6-34]; log-rank P < 0.001). On the multivariate analysis, the absence of inflammation/granuloma was significantly associated with recurrence (log-rank P < 0.001). The progression-free survival rate was higher in the granuloma and inflammation groups (75 months [95% CI: 71-79] and 82 months [95% CI: 78-86], respectively) compared with the normal histology group (33 months [95% CI: 17-48]; log-rank P < 0.001). On multivariate analysis, the absence of inflammation/granuloma was significantly associated with recurrence (log-rank P < 0.001).

Conclusion: Inflammation or granuloma in histology samples after intravesical BCG treatment for NMIBC are positive markers of response and their absence increases the risk of recurrence and progression.

Keywords: bladder cancer; granuloma; inflammation; intravesical BCG; prognostic value.