AUA 2019: The Unexpected Role of the Urinary Microbiome in Bladder Cancer Immunotherapy Efficacy

Chicago, IL ( Dr. Sweis introduced research on the role of the urinary microbiome in bladder cancer immunotherapy. He noted that there are three primary mechanisms that can affect development of and anti-tumor immune response: inherited genes, tumor oncogenes and neoantigens, and microbiome and exposures. Initial studies in mice demonstrated that genetically identical animals grew tumors differently (Figure 1). It was hypothesized that microbiome and exposures could affect tumor occurrence since species were genetically matched.

Figure 1 

According to the presenter, commensal microbiome impacted anti-cancer immune activity in mice. But is the commensal microbiome relevant to bladder cancer in people?

Studies conducted in human subjects showed that presence of beneficial bacteria and absence of harmful bacteria can predict patient’s response to anti-PD-1 therapy. 

Bladder cancer patients often fail BCG therapy. Research demonstrates that immune response measured by urine cytokines can predict response to BCG therapy. Dr. Sweis and colleagues tested a hypothesis that the urine microbiome impacts response to BCG in bladder cancer. Study team sampled urine in men and women 18 years of age and older with a previous diagnosis of localized bladder tumor and no previous BCG therapy. Specimens were collected over the course of 24 months, however only preliminary baseline data are currently available. Results showed that a difference in urine microbiome of patients with and without BCG recurrence (Figure 2). There was no significant difference in cytokines in patients with and without recurrence.

Figure 2

Presenter stated that the urine contains commensal microbiome that can be detected by sequencing, and it could regulate systemic immune response. Pilot study of 31 patients showed an association between variation of the urine microbiome and BCG responsiveness.

Presented by: Randy F. Sweis, MD; University of Chicago

Written by: Hanna Stambakio, BS, Clinical Research Coordinator, Division of Urology, University of Pennsylvania @AStambakio at the American Urological Association's 2019 Annual Meeting (AUA 2019), May 3 – 6, 2019 in Chicago, Illinois