Dosis reducida vs. dosis completa de BCG en el cáncer de vejiga: revisión sistemática y metaanálisis

Consensus document on the implications of standardization of BCG supply in the management of patients with non-muscle-invasive bladder cancer

Patients with non-muscle-invasive bladder cancer (NMIBC) in the intermediate and high-risk groups must receive adjuvant treatment with intravesical Bacillus Calmette-Guérin (BCG) following transurethral resection (TUR), as it reduces the risk of recurrence and presumably the risk of progression as well. Optimization of BCG efficacy is achieved by administering maintenance therapy. However, since many immunological aspects of the mechanism of action of BCG in the bladder remain unknown, the implementation of the optimal dose, number of instillations, strains and adequate maintenance regimen over the last decades has been heterogeneous. Additionally, this has hindered the interpretation of efficacy in terms of oncologic outcomes. This, together with the shortages of BCG in recent years, have forced scientific societies to adapt their clinical practice guidelines and modify their protocols of adjuvant treatment with BCG. This includes changes to strains, doses, and maintenance during this period of time. This consensus document evaluates the current status of adjuvant BCG treatment and the implications of BCG supply availability in the treatment of patients with NMIBC. It also addresses the implementation of novel therapies that will improve cancer prognosis and the quality of life of patients with NMIBC in the future.

Multi-omics analysis reveals that linoleic acid metabolism is associated with variations of trained immunity induced by distinct BCG strains

Trained immunity is one of the mechanisms by which BCG vaccination confers persistent nonspecific protection against diverse diseases. Genomic differences between the different BCG vaccine strains that are in global use could result in variable protection against tuberculosis and therapeutic effects on bladder cancer. In this study, we found that four representative BCG strains (BCG-Russia, BCG-Sweden, BCG-China, and BCG-Pasteur) covering all four genetic clusters differed in their ability to induce trained immunity and nonspecific protection. The trained immunity induced by BCG was associated with the Akt-mTOR-HIF1α axis, glycolysis, and NOD-like receptor signaling pathway. Multi-omics analysis (epigenomics, transcriptomics, and metabolomics) showed that linoleic acid metabolism was correlated with the trained immunity-inducing capacity of different BCG strains. Linoleic acid participated in the induction of trained immunity and could act as adjuvants to enhance BCG-induced trained immunity, revealing a trained immunity-inducing signaling pathway that could be used in the adjuvant development.

Comparative Analysis of Very Reduced vs Full Dose BCG Treatment for High-Risk Non-Muscle Invasive Bladder Cancer: A Contemporary Experience from Chile

BACKGROUND

Adjuvant bacillus Calmette-Guérin (BCG) is recommended for high-risk (HR) non-muscle invasive bladder cancer (NMIBC), but BCG shortages have led to exploration of reduced-dose regimens and shortened maintenance durations out of necessity, with limited data on treatment efficacy in Latin America.

OBJECTIVE

Oncological outcomes of HR-NMIBC patients treated with reduced (RD,1/4th dose) vs full dose (FD) BCG instillations of Danish Strain 1331 BCG.

METHODS

We performed a retrospective study of HR-NMIBC patients treated with BCG between 2003 and 2022 at our center in Santiago Chile. We stratified patients according to either RD (1/4th dose) or FD BCG. Univariate and multivariable Cox regression models were used to predict recurrence. Kaplan-Meier method was used to calculate survival estimates.

RESULTS

Of a total of 200 patients, 116 (58%) had RD and 84 (42%) FD BCG. Median follow-up was 57 months (IQR: 29-100). Patients who received FD BCG had a lower risk of recurrence (HR: 0.41, 95% CI 0.22-0.74) and high-grade (HG)-recurrence (HR: 0.30, 95% CI 0.15-0.61; p = 0.001). More patients in the RD vs FD group progressed to MIBC (10/84 vs 2/116; p = 0.18). Additionally, patients were less likely to stop BCG treatment in the RD group compared to the FD group due to toxicity (5% vs 11%, p = 0.14).

CONCLUSIONS

A 1/4th dose of Danish Strain 1331 BCG treatment was associated with worse recurrence free rate and HG-recurrence rate in our cohort. Patients with RD had lower discontinuation treatment rates due to a reduced toxicity profile. These findings would suggest that RD BCG would compromise oncological outcomes in HR-NMIBC patients.

The Impact of Dose Reduction of Bacillus Calmette-Guerin on Oncological Outcomes and Toxicity in Non-Muscle Invasive Bladder Cancer: A Systematic Review and Meta-Analysis

BACKGROUND

Bacillus Calmette-Guerin (BCG) is the standard adjuvant treatment for intermediate and high-risk non-muscle invasive bladder cancer (NMIBC) following transurethral resection of the bladder (TURB). However, the optimal dose, strain, and schedule of BCG remain unclear.

OBJECTIVE

To evaluate the impact of BCG dose reduction on oncological outcomes and toxicity in patients with non-muscle invasive bladder cancer.

METHODS

We performed a systematic review of the literature in PubMed, EMBASE, Cochrane Central Register of Controlled Trials, and ClinicalTrials.gov databases. Selected studies were analyzed for Meta Analysis using PRISMA criteria. The study focused on disease recurrence, progression, and toxicity. We also compared the oncological outcomes of the different BCG strains.

RESULTS

A total of 2963 patients in 13 randomized controlled trials were included. In recurrence analysis, we found a non-significant difference between the full dose and any dose reduction of BCG (RR = 1.17, [1.06-1.28], I2 = 0%, p = 0.7). In terms of progression, the difference was also non-statistically significant (RR: 1.12 [0.89 - 1.41], I2 = 0%, p = 0.93). In the toxicity analysis, there were more local (RR: 0.81 [0.67-0.99] I2 = 76%; p < 0.01) and systemic (RR: 0.53 [0.34-0.82] I2 = 83%; p < 0.01) side effects in the full dose group than in the dose reduction group. There were no statistically significant differences in oncological outcomes between the analyzed BCG strains.

CONCLUSIONS

Dose reduction did not affect the oncological outcomes of patients with NMIBC who received adjuvant therapy with BCG. On the other hand, dose reduction showed a significant trend towards fewer systemic and local side effects. Further studies comparing oncological and toxicity outcomes using different strains are needed.