The purpose of this podcast is to educate and to inform. This is not a substitute for professional medical care and is not intended for use in the diagnosis or treatment of individual conditions. Guests on this podcast express their own opinions, experience, and conclusions. The mention of any product, service, organization, activity, or therapy should not be construed as an ASCO endorsement. Hello and welcome to the ASCO Guidelines podcast series. My name is Shannon McKernin, and today I'm interviewing Dr. Randy Taplitz from UC San Diego Health, lead author on Antimicrobial Prophylaxis for Adult Patients With Cancer-Related Immunosuppression: ASCO and IDSA Clinical Practice Guideline Update. Thank you for being here, Dr. Taplitz. Thank you. So first, can you give us a general overview of what this guideline covers? Yes. I mean, I think we're all aware that infection in the setting of neutropenia associated with cancer chemotherapy is really a major cause of morbidity in these patients. And it's also important to be aware that prevention and appropriate management of febrile neutropenia and infection should thus be a critical focus in cancer care. So the focus of this particular guideline was to evaluate the risk and benefits of antimicrobial prophylaxis in these patients and really to determine evidence-based best practices for prevention of infection and how to go about doing that. So In this guideline, what we do is we identify the groups at risk for febrile neutropenia and really recommend settings for which prophylaxis with antibacterial, antifungal, antiviral medications are indicated. And then as well make recommendations for consideration of vaccination and other measures such as respiratory etiquette, and hand hygiene, and the like that will help reduce the risk of infection in these vulnerable patients. So since this is an update of a 2013 guideline, what are the major changes? And can you tell us a little bit about the research that informed this update? Yes. Really, when you update a guideline, one is informed by review of articles that encompass, in this setting, randomized clinical trials as well as meta analysis of interventions to prevent microbial infections in patients with neutropenia or other types of immunosuppression. And one example of this-- I think one of the better examples-- is we reviewed a large meta analysis of antibiotic prophylaxis in neutropenic patients after chemotherapy that showed that for fluoroquinolone prophylaxis resulted in really significant reductions in all cause mortality and febrile episodes, particularly in patients who were high risk, meaning the hematologic malignancy population and stem cell transplant population. And in that particular population, in fact, the number needed to treat to prevent one death was 29. So therefore, in that high risk population, really as with prior guidelines, the fluoroquinolone prophylaxis is recommended. However, we also reviewed other articles that include emerging data on some of the risks of fluoroquinolone prophylaxis. So for instance, the effect of fluoroquinolone on the intestinal microbiome and its association with selection of fluoroquinolone-resistant bacteria such as Gram-negative rods, as well as selection of organisms such as Clostridium difficile and enterococcus. And then we also reviewed fluoroquinolone toxicities. So what is added to this guideline are some qualifying statements alerting clinicians to really be aware for these concerns and to consider what the clinical spectrum of things like Clostridium difficile infection, et cetera, look like. In terms of antifungal prevention, including pneumocystis prevention, we really haven't made any major changes to this guideline with the exception that in this new guideline, the panel has also started looking at complications associated with immunotherapy and actually makes a suggestion that people consider pneumocystis prophylaxis in the setting of prolonged steroid use when it's used