ABSTRACT
Predisposition to infection in cancer patients can be broadly attributed to disease-related and therapyrelated effects. In patients with hematopoietic malignancies, disease-related factors play a prominent role due to infiltration and depletion of marrow and lymphoid elements. In addition, therapy for these diseases aims to eradicate the malignant hematopoietic and/or lymphoid populations, and thus results in profound, prolonged depletion of normal elements of the host defense network. Not surprisingly, therefore, patients with hematological malignancies are highly prone to infectious complications.1-4
For patients with solid tumors, disease-related factors, in and of themselves, play a lesser role in predisposing hosts to infection, leaving therapy-related effects as the primary determinants of the status of host defenses. While local therapies such as surgery provide a potential portal of entry for infectious pathogens, such therapies alone rarely result in serious infectious complications. The use of chemotherapy in the treatment of solid tumors has led to an improvement in outcome for a variety of malignancies, including germ cell tumors,5-7
breast cancer, small cell lung cancer,8,9 and pediatric solid tumors.10 However, this increase in survival comes at the price of an increase in the incidence of infection due to alterations in the host defense network. Disruption of normal host barriers via mucositis and central venous catheters, myeloid and lymphoid depletion, and immunosuppression related to corticosteroids are the primary factors that work together to predispose patients with solid tumors to infection (Figure 1.1). Importantly, although the incidence and severity of infectious complications is generally lower in individual patients with solid tumors compared with those with hematological malignancies, because solid tumors com11
patients with solid tumors are commonly encountered in a typical oncologic setting. For this reason, an appreciation of the factors that predispose patients with solid tumors to infection and the ability to identify particularly high-risk patients within this large population are important issues.
