Meta-analysis of efficacy comparisons between standard- and low-dose Bacillus Calmette-Guerin vaccines in managing non-muscular invasive bladder cancer.

Intravesical Bacillus Calmette-Guerin (BCG) is the first-line therapy for non-muscle-invasive bladder cancer (NMIBC), yet its clinical use is limited by high adverse event rates and a global supply shortage. A comparison was conducted to explore the effectiveness of low- vs. standard-dose BCG vaccines in patients diagnosed with NMIBC). The search queries utilized for China National Knowledge Infrastructure and Wanfang databases included the key words 'dose', 'BCG vaccine' and 'bladder cancer/bladder tumour'. Embase, PubMed and Web of Science databases were searched using the key words 'dose', 'Bacillus Calmette-Guerin vaccine' and 'urinary bladder neoplasm' to identify randomized controlled trials published up to December 2024. The relevant data were collected from the included study articles and a meta-analysis was conducted utilizing the Review Manager 5.4 software to evaluate the therapeutic effects of low- and standard-dose BCG vaccines. In total, 13 studies were included in the present meta-analysis after literature search, selection process and quality assessment. The present meta-analysis findings suggested that the recurrence rate in patients receiving low-dose therapy was notably higher compared with that in patients receiving standard-dose therapy [odds ratio (OR)=1.38; 95% CI, 1.10-1.73; P=0.006]. However, the incidence of adverse events was lower compared with that in the standard-dose treatment group (OR=0.39; 95% CI, 0.29-0.52; P<0.00001) and no marked differences in tumour progression, tumour-specific or overall mortalities were detected between the two groups (all P>0.05). The funnel plot revealed no notable publication bias. In conclusion, the present meta-analysis confirmed the effectiveness of low-dose BCG treatment for patients with NMIBC and highlighted its potentially notable advantage in managing adverse events in patients with NMIBC in the future.