Infectious complications of treatment for acute lymphoblastic leukemia in adults: Is antifungal prophylaxis necessary? A single-center retrospective cohort study

OBJECTIVE: To characterize infectious complications in adults during frontline treatment of acute lymphoblastic leukemia (ALL), evaluating the incidence of invasive fungal infections (IFI) in the absence of routine antifungal prophylaxis. METHODS: Single-center retrospective cohort study of adults with ALL (2010-2023). Patients were followed from induction through consolidation. IFI were defined using EORTC/MSG criteria. RESULTS: Among 295 patients, 119 (40.3%) developed ≥1 infection. Bacterial infections predominated, affecting 117 (39.7%) patients, whereas IFI were infrequent, occurring in 9 (3.1%) patients during induction and 4 (1.8%) during consolidation despite minimal antifungal prophylaxis. IFI-related intensive care unit admission and mortality were rare (2/295, 0.7%). No IFI occurred among patients receiving chemotherapy-free regimens. Chemotherapy-containing regimens were associated with higher bacterial infection rates during induction (38.2% vs. 10.4%, p <0.0001) and consolidation (24.2% vs. 8.3%, p =0.008). In multivariable analysis, chemotherapy-containing regimens (OR 3.39, 95% CI 1.42-8.08) and neutropenia duration ≥7 days (OR 1.85, 95% CI 1.05-3.25) independently predicted bacterial infection during induction. CONCLUSIONS: Bacterial infections represented the primary infectious burden and were associated with chemotherapy-containing regimens and prolonged neutropenia. IFI were uncommon and severe fungal outcomes were rare in this antifungal-naïve cohort. These findings support a risk-adapted approach to antifungal prophylaxis in adults with ALL, particularly for patients with established risk factors for IFI.