The article by Drs. Lesage and Portenoy is an excellent overview of current knowledge regarding the etiology, diagnosis, and treatment of fatigue in the cancer patient. Although we still have much to learn about cancer-related fatigue, noteworthy progress has been made over the past 10 years in identifying the problem, describing its consequences, establishing it as a recognized diagnostic entity, understanding its causes, and offering treatments.
This progress can be attributed to three trends in oncology practice and research. The first is the progress made in other areas of supportive oncology, most notably antiemetic control and pain management. Although not eradicated, these formerly preeminent concerns in supportive oncology have, by comparison to fatigue, receded in prevalence and impact on quality of life. This has exposed fatigue as the next most vexing symptom in cancer management.
A second trend is the increase of available therapies and, equally important, a willingness of funding agencies (public and private) to support fatigue research in oncology. Researchers tend to turn their attention to areas that hold promise of discovery and promise of funding. Cancer-related fatigue has achieved both distinctions over the past decade. With any luck, this trend will continue through a wave of studies examining the value of many pharmacologic and nonpharmacologic approaches to management.
Finally, a third trend is the popularization of a host of diverse "unproven" remedies for symptoms related to cancer and the cancer itself. Parallel to this has been the increasing attention paid by mainstream oncologists to the "whole person" with cancer. In the name of complementary, alternative, or integrative medicine, many oncology providers have associated with (or at least referred patients to) allied professionals in the delivery of ancillary treatments for a range of symptoms and concerns, including fatigue. This reflects an increasing realization that symptoms such as fatigue should not simply be dismissed as part of the cancer treatment experience.
Nevertheless, as pointed out by Lesage and Portenoy, the trend toward more fatigue research these past several years has been slow to produce results that can be immediately applied to improve patient care. Extensive work must be done to determine the many causes of fatigue in cancer patients. This work will not instantly produce effective interventions, although it will identify targets. Red blood cells, cytokines, "tumor burden," deconditioning, muscle loss, depression, and insomnia are frequently hypothesized to be causal factors. However, little is known about most of these factors and their relationship to fatigue.