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.