Association Between Initial Serum Galactomannan Level and Radiological and Clinical Outcomes of Invasive Pulmonary Aspergillosis in Patients with Hematological Malignancies

Background: Invasive pulmonary aspergillosis (IPA) is a major cause of morbidity and mortality in patients with hematological malignancies. Serum galactomannan (GM) is widely used for diagnosis, but the prognostic value of the initial GM level is not well established. Objective: To assess the association between the initial serum GM level at IPA diagnosis and the radiological and clinical outcomes at 42 and 90 days. Methods: We retrospectively reviewed adult patients with hematological malignancies, including hematopoietic stem cell transplant (HSCT) recipients, diagnosed with proven or probable IPA at Sultan Qaboos University Hospital between 2014 and 2017, according to the EORTC/MSG criteria. Demographic, microbiological, radiological, and clinical data were collected. Outcomes were assessed using three GM cut-off categories. Results: Seventy-eight patients were included. The median age was 44.5 years (range 18–76); 53.8% were male. Lymphoma (30.7%) and acute leukemia (25.6%) were the leading underlying diseases. Voriconazole was the most frequently used antifungal agent (74.3%). Prolonged neutropenia was present in 61.9%, and 30.7% had received HSCT. The mean serum GM at diagnosis was 1.95 (range 0.5–7.89). At 90 days, 30% had a complete radiological response, 51.4% partial, and 32.8% no response. Overall, 90-day mortality was 35.9%. There was no statistically significant association between initial GM level and 90-day mortality across categories (GM 0.5–3.0: 34.2% mortality; GM > 3.0: 60%; p = 0.243). Within the GM 0.5–3.0 group, complete radiological response was strongly associated with survival (95.2% alive at 90 days; p < 0.001). Conclusions: The initial serum GM level was not significantly associated with clinical or radiological outcomes at 42 or 90 days in patients with hematological malignancies and IPA. However, an early complete radiological response was strongly associated with improved survival, supporting the use of follow-up CT chest imaging to guide management.