Recent surveys of
cancer-related fatigue have documented substantial unmet needs
related to poor assessment and a limited focus on treatment
(Vogelzang
et al., 1997; Curt
et al., 2000). This type of survey is needed in other
seriously ill populations. Additional epidemiologic surveys
are needed in all these populations to better clarify the nature
of fatigue (including prevalence, severity, time course, and
phenomenology), to identify syndromes, and to document impact.
With the advent of improved sophistication in fatigue assessment
methodologies, these surveys promise to yield a strong foundation
for clinical trials and studies of fatigue mechanisms.
There have been very
few studies of management approaches for fatigue. At the present
time, treatment is based largely on clinical experience. This
has been codified in an algorithm for the management of cancer-related
fatigue (Portenoy
and Itri, 1999).
Figure
4.1 Algorithm for the Management of Cancer-related Fatigue
The algorithm for
cancer-related fatigue is useful in clarifying a broader research
agenda for clinical trials targeted to fatigue in medical illness.
For example, the algorithm notes that the initial approach to
the management of fatigue typically involves efforts to correct
potential etiologies, if it is possible and appropriate given
the goals of care. This may include elimination of nonessential
centrally-acting drugs, treatment of a sleep disorder, reversal
of anemia or other metabolic abnormalities, improvement in nutrition,
or management of major depression. All of these interventions
deserve systematic clinical study.
The reversal of fatigue
in successfully treated patients with depression lends credence
to the hypothesis that a subtype of fatigue is related to the
neurobiological substrate of depression. Studies of antidepressant
drugs with varied profiles in fatigued patients with and without
depressed mood would be illuminating.