Invasive Fusariosis in Immunocompromised Cancer Patients

Background: Invasive fusariosis (IF) is an emerging mold infection in patients with hematologic malignancies and hematopoietic cell transplantation. Outcomes remain poor due to intrinsic antifungal resistance and dependence on immune recovery. Methods: We conducted a retrospective study of 85 patients with fusariosis diagnosed at a tertiary cancer center from 2008 to 2025. Clinical characteristics, imaging findings, antifungal susceptibility, treatment, and outcomes were analyzed. Fisher exact and Kruskal–Wallis tests were used to assess associations between variables and outcomes. Results: The majority of patients had acute leukemia and developed IF during profound neutropenia. Disseminated disease with pulmonary and sinus involvement was common. Susceptibility testing (n = 48) confirmed high minimum inhibitory concentrations to amphotericin B and azoles across Fusarium solani and F. oxysporum species complexes. Antifungal exposure at the time of suspicion was associated with amphotericin B resistance ( P = 0.049). Antifungal regimen type (amphotericin B, voriconazole, or combination) was not associated with survival ( P = 0.826). Duration of neutropenia was not statistically linked to outcome ( P = 0.244). Overall, in-hospital all-cause mortality remained high, particularly among persistently immunocompromised patients. Conclusions: Fusariosis remains a highly lethal infection in hematologic patients, with limited impact of antifungal regimen selection on in-hospital mortality. Survival appears more strongly associated with host immune recovery than with currently available antifungal therapy. Novel antifungals such as fosmanogepix warrant urgent evaluation to improve outcomes in this population.