Comparing Clinical Efficacy of Different Bacillus Calmette-Guérin Strains in Patients with T1 High Grade Bladder Cancer

Abstract

Abstract Purpose: The aim of our study is to clarify the clinical efficacy between two different Bacillus Calmette-Guérin (BCG) strains, TICE strain (Oncotice) and Connaught strain (ImmuCyst) as first line intravesical instillation therapy in patients with T1 high grade bladder urothelial cell carcinoma. Methods: Between 2008 to 2022, patients with new diagnosed T1 high-grade bladder cancer received transurethral resection of bladder tumor (TURBT) and subsequent intravesical instillation therapy in Taichung Veterans General Hospital were retrospectively enrolled in this study. Patients were categorized into Connaught group and TICE group, based on the specific BCG strain administered for treatment. Kaplan-Meier and Cox proportional hazards models analyzed BCG strain effects on recurrence, progression, and side effects. Results: Among 147 patients, 53 patients received Connaught strain and 94 patients received TICE strain. The median follow-up time was 89 months in the Connaught group and was 28 in the TICE group. The completion rate of BCG induction instillation was 92.45% in the Connaught group and 91.49% in the TICE group (p=1.00). The three-year recurrence-free survival rate was 71.7% in the Connaught group and 63.83% in the TICE group (p=0.33), while the three-year progression-free survival rate was 96.23% in the Connaught group and 89.36% in the TICE group (p=0.21). On Cox regression test, carcinoma in situ and ≥ 8 lesions were significant predictors for recurrence. Both of the two regimens exhibited no significant difference in terms of recurrence and progression. As for side effects, the frequency of cystitis (p = 0.011), UTI (p = 0.021), and hematuria (p = 0.042) were significant lower in the TICE group. The complication rates according to the Cleveland Clinic grading system showed no significant difference among the two groups (p=0.13). Conclusions: In our study of T1 high-grade bladder urothelial cell carcinoma, both the Connaught strain and TICE strain BCG demonstrated comparable completion rates, 3-year recurrence-free survival rates, and 3-year progression-free survival rates. Adverse events were more frequent in the Connaught group, though the majority were of low grade. Given the global shortage of BCG, additional comparisons of the different strains are warranted to enable clinicians to validate their efficacy.