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.