Does asymptomatic bacteriuria affect the response to intravesical bacillus Calmette-Guérin?

An exploratory study investigating the impact of the bladder tumor microbiome on Bacillus Calmette Guerin (BCG) response in non-muscle invasive bladder cancer

PURPOSE

Intravesical Bacillus Calmette-Guerin (BCG) is standard of care for intermediate- and high-risk non-muscle invasive bladder cancer (NMIBC). The effect of the bladder microbiome on response to BCG is unclear. We sought to characterize the microbiome of bladder tumors in BCG-responders and non-responders and identify potential mechanisms that drive treatment response.

MATERIALS AND METHODS

Patients with archival pre-treatment biopsy samples (2012-2018) were identified retrospectively. Prospectively, urine and fresh tumor samples were collected from individuals with high-risk NMIBC (2020-2023). BCG response was defined as tumor-free 2 years from induction therapy. Extracted DNA was sequenced for 16S rRNA and shotgun metagenomics. Primary outcomes were species richness (α-diversity) and microbial composition (β-diversity). Paired t-tests were performed for α-diversity (Observed species/Margalef). Statistical analysis for β-diversity (weighted and unweighted UniFrac distances, weighted Bray-Curtis dissimilarity) were conducted through Permanova, with 999 permutations.

RESULTS

Microbial species richness (P < 0.001) and composition (P = 0.001) differed between BCG responders and non-responders. Lactobacillus spp. were significantly enriched in BCG-responders. Shotgun metagenomics identified possible mechanistic pathways such as assimilatory sulfate reduction.

CONCLUSION

A compositional difference exists in the tumor microbiome of BCG responders and non-responders with Lactobacillus having increased abundance in BCG responders.

Recurrent Bacteriuria as a Prognosis Marker in the Adjuvant Treatment of Non-Muscle Invasive Bladder Cancer

PURPOSE

Bacteriuria may affect the response to adjuvant therapy in non-muscle invasive bladder cancer (NMIBC). The main aim of this study was to examine the effect of recurrent bacteriuria (RB) on the prognosis of NMIBC in women receiving intravesical therapy.

MATERIALS AND METHODS

We designed a prospective observational study from 2012 to 2019. We included women with bladder cancer treated with transurethral resection of the bladder (TURB) and adjuvant intravesical treatment. Significant bacteriuria was defined as a presence in urine cultures at or above 100,000 colony-forming units per millilitre. The recurrent bacteriuria group included patients with significant bacteriuria in at least two determinations in 6 months or in 3 or more determinations in a year. The institutional board approved the study.

RESULTS

One hundred thirty-six patients diagnosed with NMIBC participate in the study, of whom 100 met the inclusion criteria. During follow-up, 48 were categorized in the RB group and 52 formed the non-bacteriuria group (NB).

RB GROUP HAD A BETTER OUTCOME

Eight patients (16.67%) experiencing a recurrence of the same grade, with no progression to a higher-grade tumor or muscle-invasive tumor. In the NB group, 18 (34.6%) patients presented a recurrence (P = .001) and 22 (42.3%) progressed to a higher-grade tumor or muscular invasion (P = .001). The presence of RB was identified as a predictor of good response in multivariate regression with a relative risk of 0.13 (P = .018) CONCLUSIONS: Female patients with RB had a better response to adjuvant treatment for NMIBC. The RB group showed lower rates of tumor recurrences and progression.

Quinolone Prophylaxis in Conjunction with Bacillus Calmette-Guérin Instillations for Bladder Cancer: Time To Reconsider the Evidence and Open the Quinolone Box?

Adjuvant bacillus Calmette-Guérin (BCG) instillations represent a cornerstone in the treatment of non-muscle-invasive bladder cancer. Instillation schedule and dose modifications have been evaluated in efforts to reduce the incidence of adverse events (AEs), but none so far has the same treatment efficacy as the full-dose recommended schedule. It has been shown that prophylactic quinolone use in conjunction with BCG instillations reduces AE incidence and improves timely completion of instillation regimens and patient survival. However, the European Medicines Agency imposed restrictions on the use of quinolones in 2019 because of side effects. Nevertheless, rational use of quinolone prophylaxis could be considered for selected individuals treated with BCG without risk factors for quinolone-associated side effects in conjunction with patient information about side-effect symptoms. PATIENT SUMMARY: Bladder instillations of BCG (bacillus Calmette-Guérin) are used in the treatment of non-muscle-invasive bladder cancer. Antibiotics from the quinolone class can reduce the adverse effects of BCG and help patients in completing the treatment course; however, these antibiotics have their own side effects. Our mini review suggests that the antibiotics could be used in selective cases if patients are given adequate information on these side effects and their symptoms.

The indispensable role of urinalysis for patients undergoing treatment for nonmuscle invasive bladder cancer

Despite several efforts in the search for noninvasive biomarkers to provide prognostic information for noninvasive muscle bladder cancer, none have shown significant potential. In this context, standard urinalysis is still necessary to provide many data. This method is an inexpensive, simple, and easy-to-repeat tool to follow-up patients over time. Urinalysis does not fall within study protocols and allows evaluation of the immune activation/response (even if indirectly). As such, this method can certainly provide useful information for prognosis.

Treatment Outcomes of High-Risk Non-Muscle Invasive Bladder Cancer (HR-NMIBC) in Real-World Evidence (RWE) Studies: Systematic Literature Review (SLR)

Background

To date, there has been limited synthesis of RWE studies in high-risk non-muscle invasive bladder cancer (HR-NMIBC). The objective of this research was to conduct a systematic review of published real-world evidence to better understand the real-world burden and treatment patterns in HR-NMIBC.

Methods

An SLR was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines with the scope defined by the Population, Intervention Comparators, Outcomes, and Study design (PICOS) criteria. EMBASE, MEDLINE, and Cochrane databases (Jan 2015–Jul 2020) were searched, and relevant congress abstracts (Jan 2018–Jul 2020) identified. The final analysis only included studies that enrolled ≥100 patients with HR-NMIBC from the US, Europe, Canada, and Australia.

Results

The SLR identified 634 RWE publications in NMIBC, of which 160 studies reported data in HR-NMIBC. The average age of patients in the studies was 71 years, and 79% were males. The rates of BCG intravesical instillations ranged from 3% to 86% (29–95% for induction and 8–83% for maintenance treatment). Five-year outcomes were 17–89% recurrence-free survival (longest survival in patients completing BCG maintenance), 58–89% progression-free survival, 71–96% cancer-specific survival (lowest survival in BCG-unresponsive patients), and 28–90% overall survival (lowest survival in patients who did not receive BCG or instillation therapy).

Conclusion

BCG treatment rates and survival outcomes in patients with HR-NMIBC vary in the real world, with better survival seen in patients completing maintenance BCG, responding to treatment, and not progressing to muscle-invasive disease. There is a need to better understand the factors associated with BCG use and discontinuation and for an effective treatment that improves outcomes in HR-NMIBC. Generalization of these results is limited by variations in data collection, reporting, and methodologies used across RWE studies.