ABSTRACT
The use of intensive chemotherapeutic regimens, hematopoietic stem cell
transplantation, and other therapeutic modalities, has increased the remission and
cure rates of many cancer patients. These modalities have also been associated
with more severe myelosuppression and immunosuppression, increasing the
frequency of severe, sometimes fatal, infection. Although substantial progress
has been made in prevention, early diagnosis, and treatment of infections, the
spectrum of organisms causing these infections undergoes periodic changes, new
opportunistic pathogens emerge, and common organisms develop multiple
mechanisms of resistance. Also, patients today are less restricted in their
activities and may be exposed to human, plant, or animal pathogens more fre-
quently than in the past, leading to an increasing proportion of infections orig-
inating outside the hospital. Additionally, the usual signs and symptoms of
infection including fever may be minimal or absent, especially among severely
neutropenic patients and those receiving adrenal corticosteroids. Consequently,
patients must be monitored carefully, especially during periods of increased risk.
The availability of sophisticated technology such as CT scan, antigen detection,
and molecular techniques (PCR) have assisted in the diagnosis of some infec-
tions and offers promise for greater success in the future. Nevertheless, a specific
diagnosis of infection is often not possible, and empiric therapy must be
administered on the basis of local epidemiology and susceptibility/resistance
patterns. In recent years, it has become possible to stratify patients into cate-
gories such as high-risk and low-risk for the development of severe infections
and associated complications. Treatment strategies such as early discharge,
outpatient management, and orally administered drugs are now commonplace in
low-risk patients.
