Introduction
Fatigue is a common symptom in patients with cancer1–3 that can adversely impact
quality of life (QoL).4 Many studies report that for cancer patients receiving chemotherapy, fatigue incidence is ∼60%;5 however, reported prevalence rates vary widely
depending on how fatigue is defied and measured, as well as the patient population
studied.
Although it is diffiult to manage fatigue directly caused by disease, effective
therapies exist for chemotherapy-induced anemia (CIA), and correcting anemia in patients receiving chemotherapy is, therefore, recommended
as a method for managing fatigue.6–10 The effectiveness of
erythropoiesis-stimulating agents (ESAs) and/or red blood
cell (RBC) transfusions in managing CIA by raising hemoglobin (Hb) levels is well documented.11,12 However, data on
the impact of such treatments on fatigue are more limited.
A major diffiulty in studying fatigue in cancer is that
its etiology is often multifactorial, with both disease- and
treatment-related effects likely to contribute. Consequently,
many tools aimed at assessing fatigue in patients with cancer
have been developed. Multi-item measures, such as the
Functional Assessment of Cancer Therapy-Fatigue (FACT-F)
subscale, are generally preferred in research settings as they
aim to capture the complex nature of cancer-related fatigue.
Single-item measures (eg, the fatigue visual analog scale
[VAS] 13) capture a patient’s perception of their fatigue and
are often preferred in clinical practice as they are quick and
simple to apply. However, as the level and impact of fatigue
for a given patient is subjective, the clinical relevance of a
change in score can sometimes be diffiult to interpret.
In the eAQUA (electronic assessment of QoL in patients
with symptomatic anemia) clinical practice study, we used
an anchor-based approach14–17 to calculate the minimally
important difference (MID) for a fatigue-related QoL
improvement in patients with CIA receiving darbepoetin
alfa (DA) or another ESA according to current European
indication. The MID was defied as the smallest change in
QoL score perceived to be benefiial by this population of
patients. eAQUA also aimed to assess the effectiveness of
ESAs at improving Hb levels, which was an important assessment because although DA has been available for several
years, there are few data on its use in line with the recently
updated European indication for symptomatic CIA.18 This
mandates that DA should now only be used in patients with
a baseline Hb level of #10 g/dL. eAQUA also adds to the
limited data relating to improvements in Hb levels and QoL
in clinical practice.