Baseline Chest Computed Tomography for Early Diagnosis of Invasive Pulmonary Aspergillosis in Hemato-oncological Patients

Clin Infect Dis. 2019 Mar 11. pii: ciz194

Contributed by Dr Tanu Singhal

This study aimed to assess the value of a baseline chest CT for early diagnosis of invasive pulmonary aspergillosis in hemato-oncological patients. All patients admitted for induction or salvage chemotherapy between October 2015 to September 2017 for acute myeloid leukemia (AML) or for allogeneic hematopoietic stem cell transplantation (HSCT) underwent routine baseline chest CT. Between July 2016 and April 2017, they also included those patients undergoing autologous HSCT. Patients with abnormal CT underwent diagnostic bronchoscopy with BAL sampling. Laboratory processing of BAL fluid included fungal stain, fungal culture, aspergillus DNA PCR, and Galactomannan (GM) antigen detection. Serum GM was also measured. Patients with the diagnosis with IPA, according to the EORTC diagnostic criteria, were commenced on treatment with voriconazole, whereas others were given antifungal prophylaxis with posaconazole or fluconazole for the duration of neutropenia. During the neutropenic period they measured GM in serum twice weekly, and repeated chest CT for patients with persistent fever unresponsive to broad-spectrum antibiotic coverage.

Of the 295 patients were included in study, 107 were admitted for induction chemotherapy for newly diagnosed AML, 24 were admitted for salvage chemotherapy; 82 were admitted for allogeneic HSCT and 82 were admitted for autologous HSCT. Baseline chest CT was abnormal in 91 (30%). Of these, 49 (17%) patients had significant pathological findings and underwent bronchoscopy with BAL. A diagnosis of IPA on admission was made in 15 (15/295, 5%) patients. Additional 29 patients (29/295, 9.8%) were diagnosed with IPA subsequently during hospitalization. All 44 cases were probable IPA, 40 had positive GM in BAL, 8 had positive GM in serum and 6 had growth of Aspergillus spp. in fungal culture from BAL. In addition, 11 had positive Aspergillus PCR in BAL not used as a sole microbiological criterion.

Among 107 patients with newly diagnosed AML 18.7% (20/107) were diagnosed with proven or probable IPA at any time during the hospitalization for induction chemotherapy, more than half of these patients (11/20, 55%) were diagnosed on admission. Among patients with AML half the burden of IPA was present before start of chemotherapy.

The authors concluded that routine baseline chest CT may lead to early diagnosis and treatment of infection leading to reduced morbidity and mortality. Important limitations of the study included a single centre study, small sample size and lack of information on survival outcomes.