BACKGROUND: Bacillus Calmette-Guérin (BCG) immunotherapy plays a key role in patients with bladder cancer. The shortage of intravesical BCG has motivated researchers to seek alternatives with equivalent efficacy If other alternative intravesical agents have equivalent efficacy compared to BCG, then it may be feasible to replace standard BCG with alternative options. METHODS: We searched all relevant evidence in multiple sources and key data was extracted from included studies. Conventional and network meta-analysis were conducted so that pooled odds ratios (ORs) for the event of tumor recurrence and progression can be computed. The relative efficacy of different intravesical instillation procedures was computed by pooled odds ratios and their 95% confidence or creditable intervals. Besides, several key model assumptions were evaluated in our analysis. RESULTS: Three intravesical instillation procedures have the potential for preventing tumor recurrence: standard-dose BCG (BCG_SD), Epirubicin (EPI) and Mitomycin C (MMC) (ORs < 1). Patients with BCG SD also exhibited a decreased risk of tumor recurrence and progression compared to those with EPI. No significant difference in the risk of tumor recurrence or progression was detected between patients treated with BCG_ SD and those with low-dose BCG (BCG_LD). Results of SUCRA indicated that BCG_EPI, BCG_ MMC and BCG SD had higher rankings with respect to tumor recurrence and progression. CONCLUSIONS: BCG SD, EPI and MMC exhibited established efficacy for preventing tumor recurrence in postoperative BC patients. The efficacy of BCG may not be significantly reduced if standard dose was reduced to a lower level. However, there is no consensus suggesting that intravesical BCG with standard dose can be replaced by alternating or sequentially combined intravesical instillation therapies.