Galactomannan and computed tomography-based preemptive antifungal therapy in neutropenic patients at high risk for invasive fungal infection: a prospective feasibility study.

BACKGROUND: Empirical antifungal therapy is the standard treatment for persistent or relapsing antibiotic-resistant neutropenic fever. However, overtreatment resulting in increased toxicity and treatment-related cost is a major shortcoming of such therapy. We assessed the feasibility of a "preemptive" approach based on the incorporation of sensitive, noninvasive diagnostic tests for consecutive high-risk neutropenic patients who had received fluconazole prophylaxis while avoiding empirical therapy.
METHODS: A total of 136 treatment episodes for persons who were at risk of acquiring invasive fungal infection (IFI) were screened for the presence of galactomannan with an enzyme immunoassay. A diagnostic evaluation, which included thoracic computed tomography scanning (HRCT) and bronchoscopy with lavage, was performed on the basis of well-defined clinical, radiological, and microbiological criteria. Only seropositive patients and patients with a positive microbiological test result plus supportive radiological findings received liposomal amphotericin B.
RESULTS: Neutropenic fever developed in 117 episodes, of which at least 41 episodes (35%) satisfied existing criteria for empirical antifungal therapy. However, our protocol-driven preemptive approach reduced the rate of antifungal use for these episodes from 35% to 7.7% (a 78% reduction) and led to the early initiation of antifungal therapy in 10 episodes (7.3%) that were clinically not suspected of being IFI. No undetected cases of invasive aspergillosis were identified; 1 case of zygomycosis was missed. Breakthrough candidemia was diagnosed by conventional culture techniques and was treated successfully. With use of a preemptive approach, the 12-week survival rate for patients with IFI was 63.6% (it was 63.1% for those with invasive aspergillosis).
CONCLUSION: Preemptive therapy based on enzyme immunoassay and HRCT reduced the exposure to expensive and potentially toxic drugs and offered effective antifungal control, but it failed to detect non-Aspergillus IFI.