Safety and efficacy of various strains of bacille Calmette-Guérin in the treatment of bladder tumours in standard clinical practice

Abstract

Background: The natural progression of bladder tumours (nonmuscle-invasive bladder cancer [NMIBC]) is recurrence with a high rate of progression. Bacille Calmette-Guérin (BCG) has been shown effective in reducing these rates, but there are few comparative studies between strains.

Material and methods: An observational, prospective and multicentre registry studied 433 patients with a 12-month follow-up visit from 961 registered patients, assessing disease-free survival (DFS), progression-free survival (PFS) cancer-specific survival (CSS) and adverse effects. We studied the Tice, Russian, Tokyo, Connaught and RIVM strains.

Results: The sociodemographic data, NMIBC history, comorbidities, size, number, stage, grade, associated carcinoma in situ and transurethral resection were well balanced. DFS: There were 85 relapses (19.6%). The median DFS time was 20months. When comparing the various strains, we detected no statistically significant differences (log-rank test; P=.93). LPS: There were 33 cases of progression (7.62%). When comparing the various strains, we detected no statistically significant differences (log-rank test; P=.69). CSS: Seven patients died (1.68%). When comparing the various strains, we detected no statistically significant differences (log-rank test; P=.93). In terms of safety, 33.3% of the patients presented some type of adverse effect, mostly lower urinary symptoms (no urinary tract infections) <48h, >48h and haematuria. According to the Common Toxicity Criteria of the European Organisation for Research and Treatment of Cancer, 92.7% of the patients were grade1. There were no statistically significant differences between the strains.

Conclusions: In this intermediate analysis, the risk of recurrence, progression, specific death and safety were independent of the BCG strain employed.

Keywords: BCG; Bladder cancer; Cepas; Cáncer vesical; Strains.