Infections in Cancer Patients PDF

Preface

The field of infectious diseases in the cancer patient has undergone great metamorphosis and growth over the last decade. We have attempted to take an easy-to-read, well-organized approach to managing infections in oncological patients. With an emphasis on the underlying malignancy as the central theme, infections unique to that cancer and its therapy can be readily accessed and understood. Previous texts that emphasize organisms as the major theme are frequently hard to follow and less useful for management of the individual patient. By describing the major immune defects inherent to each malignancy and their therapy we allow for more accurate and timely diagnosis of the unique pathogens acquired. In addition, the malignancy and its therapy over time may alter the immune system and lead to anatomical changes that predispose to a changing spectrum of pathogens. For example, progressive growth oflung cancer can obstruct a major bronchus and result in postobstructive pneumonia, whereas radiation therapy to the lung may impair alveolar macrophage function and create lung paremchymal changes to form a cavity, both of which favor invasive aspergillus infection.

As patients are being treated with more aggressive chemotherapeutic regimens, profound immunosuppression for longer periods of time is occurring. This period of immunodeficiency is an open invitation to the invasion of a multitude of intrinsic and extrinsically acquired organisms. By under-standing the period of vulnerability of the host throughout the periods of active malignancy growth, neutropenia, and cell-mediated immunodeficienies, the clinician can choose the appropriate antimicrobial agents to prevent or treat the most dangerous and most common infections.

Using a number of relevant and recent publications, the most important infections associated with each malignancy are presented. In addition, the susceptibility to different infections over the course of a chronic progressive malignancy is presented. For example, patients with newly diagnosed multiple myeloma are susceptible to pneumococcal infections of the respiratory tract. However, as the disease progresses and chemotherapy is used to control it, Pseudomonas aeruginosa infection of the respiratory tract becomes more prominent.

Neutropenia, the most common byproduct of cancer therapy can be broken down into periods of time when predominant pathogens change. Likewise, antimicrobial therapy must be altered to reflect this transition. For instance, gram-negative and gram-positive bacterial infections dominate the first week of neutropenia. During the second week, candida sp infections become important, followed by aspergillus infections into the third week. Therefore, changes in treatment are frequently necessary as neutropenia progresses.

In summary, the cancer patient's risk of infection can be tracked from diagnosis to cure or cancer-related death. By understanding the underlying immune status of each patient during cancer therapy, the best choices for infection management can be made. Using pictures to illustrate infectious disease presentations and easy-to-follow tables of pertinent groups of diseases, the clinician interested in cancer-related infections has a useful resource for patient evaluations and staff education.

We dedicate this book to all the patients who have valiantly battled cancer, endured the toxicity of its treatment, and overcome the ensuing microbial invasion during their most vulnerable moment.