Considerations for the prevention of infectious complications in patients with cancer.

Methods of preventing the infectious complications that occur in patients undergoing therapy for cancer have been the focus of considerable research. Because infections arise from both the endogenous microbial flora and newly acquired organisms and because the pathogens include bacteria, fungi, viruses, and/or parasites and affect a number of different body sites, it has been difficult to conceive of a single or simple method of controlling these multiple infectious etiologies. The suppression or elimination of the host's own microbial flora by the use of various prophylactic antibiotics and the reduction in the patient's acquisition of new organisms by the use of isolation techniques have received the greatest attention. While a number of these approaches (including total protected isolation, nonabsorbable antibiotics, trimethoprim-sulfamethoxazole, selective decontamination, and most recently the quinolones) have appeared to reduce the incidence of infections, few have stood the test of time. The advantages and disadvantages of each of these methods are reviewed, and newer promising areas for current and future investigation are considered.