Is there any difference between bacillus calmette-guerin (BCG) strains used in intravesical treatment in NON-muscle invasive bladder cancer patients in terms of efficacy and side effects? comparison of rivm and russian strains

Aim: To compare the differences in adverse effects and efficacy profile between Bacillus Calmette-Guerin (BCG) RIVM and RUSSIAN strains in management of non-muscle invasive bladder cancer. Materials and Methods: Between January 2019 and December 2022, we prospectively followed up patients who applied to Ankara University Medical Faculty İbn-i Sina Hospital Urology Clinic with a preliminary diagnosis of bladder tumor. After a transurethral resection of the tumor was performed, we classified the patients into low, medium, high and very high risk groups. The target group of our study was those patients in the intermediate risk group, high risk group and very high risk group who did not accept radical cystectomy and/or were not suitable for radical cystectomy. Intravesical BCG treatment was planned for these patients, we randomized them into two separate groups and followed them prospectively: Group 1: RIVM BCG strain (n=61) and Group 2: RUSSIAN BCG strain (n=64). We evaluated and compared the patients in these two groups in terms of recurrence and progression through periodic cystoscopic controls. In addition, the patients were asked to fill in a follow-up form before every intravesical BCG administration. By these forms, the side effects related to BCG administration were recorded. Results: Demographic and pathological characteristics of both groups were similar and showed a homogeneous distribution. Follow-up time was calculated as 26.4 ± 9.8 months for Group 1 and 27.8 ± 9.6 months for Group 2. Patients in Group 1 received an average of 15 BCG doses, and those in Group 2 received an average of 14 BCG doses. Looking at the side effect profile; In group 1: No side effects were observed in 12 patients, class 1 side effects were observed in 34 patients, class 2 side effects were observed in 12 patients, and class 3 side effects were observed in 3 patients. No class 4 side effects were observed in group 1 patients. In group 2, 18 patients had no side effects, 28 patients had class 1 side effects, 12 patients had class 2 side effects, 5 patients had class 3 side effects, and 1 patient had class 4 side effects (P= 0.545). When we compared the patients in terms of progression and recurrence; Progression was observed in 4 patients (6.6%) in Group 1, and in 8 patients (12.5%) in Group 2 (P= 0.365). However, recurrence was seen in 17 patients (27.9%) in Group 1, and in 19 patients (29.7%) in Group 2 (P=0.822). Recurrence-free and progression-free survival rates of the two groups were compared by Kaplan-Meier analysis, and no significant difference was observed between the two groups (p= 0.875 for recurrence, p= 0.267 for progression). Conclusion: In this randomized prospective study comparing BCG RIVM strain and BCG RUSSIAN strain in terms of efficacy and side effects; At the end of a mean follow-up period of 27 months, no significant difference was found between the two strains in terms of disease progression, recurrence and side effects.