Applying the principles of evidence-based medicine to febrile neutropenia (FN) results in a more limited set of practices than expected. Hundreds of studies over the last 4 decades have produced evidence to support the following: (1) risk stratification allows the identification of a subset of patients who may be safely managed as outpatients given the right health care environment; (2) antibacterial prophylaxis for high-risk patients who remain neutropenic for Ն 7 days prevents infections and decreases mortality; (3) the empirical management of febrile neutropenia with a single antipseudomonal beta-lactam results in the same outcome and less toxicity than combination therapy using aminoglycosides; (4) vancomycin should not be used routinely empirically either as part of the initial regimen or for persistent fever, but rather should be added when a pathogen that requires its use is isolated; (5) empirical antifungal therapy should be added after 4 days of persistent fever in patients at high risk for invasive fungal infection (IFI); the details of the characterization as high risk and the choice of agent remain debatable; and (6) preemptive antifungal therapy in which the initiation of antifungals is postponed and triggered by the presence, in addition to fever, of other clinical findings, computed tomography (CT) results, and serological tests for fungal infection is an acceptable strategy in a subset of patients. Many practical management questions remain unaddressed.
Evidence-based medicinePracticing evidenced-based medicine means "integrating individual clinical expertise with the best available external clinical evidence from systematic research." 1 This definition acknowledges that anyone's personal experience is limited but valuable, and then assumes that systematic research has produced evidence applicable to the particular case. The key point is the qualifier "best," meaning that the evidence has to be appraised, which is not easy. Some helpful online resources that focus on evidence-based medicine include http://www.cebm.net, http://plus.mcmaster.ca/EvidenceUpdates/Default.aspx, and http:// acpjc.acponline.org/.The "right" hierarchy of evidence is a matter of academic debate, although the principles are agreed upon: a properly conducted randomized controlled trial (RCT) is usually better evidence than an observational study, which is generally better than a case series, which beats a case report. A systematic review of all RCTs usually is preferable over a single trial. At the bottom of the ladder is "mechanism-based reasoning" (very frequently used during ward rounds when there is nothing better). An example of how different levels of evidence may support different conclusions regarding the use of vancomycin in neutropenic patients is presented in Table 1. This example uses the ranking proposed by the Oxford-based Centre for Evidence-based Medicine (CEBM). 2,3 When confronted with a clinical decision, instead of personally sieving through the evidence, one may look up guidelines offered by professiona...