Fungal infections in leukemia patients: how do we prevent and treat them?

Invasive fungal infections (IFIs) remain an important cause of morbidity and mortality in patients with acute or chronic leukemia. Advances in the pharmacotherapy of fungal infections and a shift in the epidemiological characteristics of fungal pathogens toward fluconazole-resistant Candida species and saprophytic molds have placed a greater emphasis on selection of broader-spectrum agents for empirical therapy of IFIs in this high-risk population. Newer diagnostic modalities, such as the Aspergillus galactomannan test, the 1,3-beta-d-glucan test, and polymerase chain reaction detection of fungal DNA, may facilitate the earlier diagnosis of IFIs, but their role in detecting breakthrough infection and their usefulness as a marker to withhold antifungal therapy in high-risk leukemia patients with IFI are less obvious, especially in patients who are receiving antifungal prophylaxis. Only 2 strategies have been shown in prospective studies to improve survival from mold infection in patients with acute myelogenous leukemia or myelodysplastic syndrome: (1) preemptive initiation of antifungal therapy at first sign of invasive aspergillosis on computed tomography (CT) scan and (2) antifungal prophylaxis with posaconazole. CT-guided treatment decisions are more complex in patients with advanced leukemia, however, because of concomitant infection or relapsing malignancy. Similarly, posaconazole is often not a viable prophylaxis or treatment option in patients with poor oral intake, gastrointestinal dysfunction, or possible drug interaction (eg, proton pump inhibitor prophylaxis in patients on high-dose glucocorticosteroids). As a result, the management of IFI in patients with leukemia demands an individualized treatment plan.