Bacterial Pneumonia in Patients with Cancer: Novel Risk Factors and Management

Abstract

Bacterial pneumonias exact unacceptable morbidity on patients with cancer. Although the risk is often most pronounced among patients with treatment-induced cytopenias, the numerous contributors to life-threatening pneumonias in cancer populations range from derangements of lung architecture and swallow function to complex immune defects associated with cytotoxic therapies and graft-versus-host disease. These structural and immunologic abnormalities often make the diagnosis of pneumonia challenging in patients with cancer and impact the composition and duration of therapy. This article addresses host factors that contribute to pneumonia susceptibility, summarizes diagnostic recommendations, and reviews current guidelines for management of bacterial pneumonia in patients with cancer.

Keywords: Bacterial pneumonia; Cancer; Hematologic malignancy; Immunocompromised host pneumonia; Neutropenia; Stem cell transplant.

Figure 1. Host factors that promote bacterial pneumonia susceptibility in cancer patients

Although cancer patients’ medical encounters expose them to uncommon, virulent and drug-resistant pathogens, much of the increased risk of pneumonia in this population derives from complex and often concurrent impairments of host defense. Shown are frequent defects in cancer patients’ pneumonia defenses, caused by insults both in and outside the lungs. CNS, central nervous system.

Figure 2. Radiographic presentations of bacterial pneumonia in cancer patients

CT images of cancer patients with documented bacterial pneumonias. (A) Multifocal lobar consolidation in a patient with acute myelogenous leukemia and Legionella micdadei pneumonia. (B) Diffuse ground-glass infiltrates in a patient with chronic myelomonocytic leukemia and Raoultella planticola pneumonia. (C) Peribronchial nodules (and small, chronic pleural effusions) in a patient with myelodysplastic syndrome and Stenotrophomonas maltophilia pneumonia. (D) Multidrug-resistant Klebsiella pneumoniae pneumonia presenting as a single mass in a patient with aplastic anemia. (E) Diffuse, mixed alveolar and interstitial infiltrates in a patient with myelodysplastic syndrome and Pseudomonas aeruginosa pneumonia. (F) Methicillin-resistant Staphylococcus aureus pneumonia presenting as new nodules on a background of pre-existing nodules in a patient with renal cell carcinoma metastatic to the lungs.