BACKGROUNDInvasive pulmonary aspergillosis (IPA) is a life‐threatening infection in immunocompromised patients. The outcome of such infections depends on early diagnosis and prompt initiation of therapy. The objective of the current study was to determine the significant predictive factors that characterize IPA in patients with cancer.METHODSThe clinical characteristics and computed tomography (CT) findings for 47 cases with IPA were retrospectively reviewed and compared with 49 controls (patients diagnosed on autopsy with nonfungal pneumonias). Data from all 96 patients were modeled using multivariate logistic regression. Subgroups of patients with common characteristics and outcomes were identified.RESULTSLeukemia, neutropenia, cavitation, and nodular lesions occurred significantly more often among cases than controls (P = 0.04, 0.004, 0.04, and 0.02, respectively). A quantitative scoring system was developed that could be used to identify patients as being at low, medium, and high risk for IPA.CONCLUSIONSIPA should be highly suspected in leukemia patients with profound neutropenia, pleuritic chest pain, and cavitary or nodular lesions detected on CT scan. These predictive factors can be used to indicate when early prophylactic and therapeutic antifungal interventions should be initiated. Cancer 2006. © 2006 American Cancer Society.