Can consideration of the microbiome improve antimicrobial utilization and treatment outcomes in the oncology patient?

The need to provide effective and timely antimicrobial treatment to cancer patients with infections is well recognized but tempered by preliminary, but accumulating, evidence that antibiotic-induced microbiome dysbiosis affects cancer therapy response, noninfectious toxicities, and infectious complications. Given only a minority of empirically treated cancer patients are proven to have a true bacterial infection, it is important to consider the potential negative consequences of extensive broad-spectrum antimicrobial use on the commensal microbiota. Herein, we review the literature substantiating the dilemma oncologists face when treating suspected or documented infections with respect to the interaction between the host microbiome, antibiotics, and cancer-related clinical outcomes. We propose microbiome-based explorations that could assist oncologists in optimizing treatment strategies for cancer-related infections as well as the cancer itself. In addition, we discuss knowledge gaps and challenges in this nascent field that must be addressed to deliver medically relevant, translational applications. We anticipate that the emerging knowledge regarding the role of the microbiota in the health of cancer patients may cause a reappraisal of the manner in which antibiotics are used in the oncologic setting and how microorganisms are viewed by oncologists.