in a specific form of cancer raising the question of how various
factors could work together to weave a complex picture of fatigue. The
post correctly includes a definition for cancer-related fatigue, but
does not differentiate between the relatively mild tiredness
associated with depression and the more severe forms. Although doctors
cannot experience the specific fatigue of their patients it might be
assumed that most adults have experienced the lassitude related to
depression at some point in their life and can differentiate between
the tiredness associated with depression and more severe organic forms
of fatigue - even though the physician or research has only their own
experiences to draw from.
Fatigue and Mesothelioma
AUG 15, =9211 5:51 AM
Fatigue is a common symptom of advanced mesothelioma. Fatigue is also
commonly linked with cancer treatment and has an occurrence rate of
90% among patients receiving chemotherapy. There are many potentially
underlying causes for both the symptoms. In majority of patients, the
etiology of both the symptoms is multifactorial, with several of these
contributing interrelated abnormalities. For instance, in a study
involving patients with advanced cancer, it was noticed that fatigue
correlated significantly with the intensity of dyspnea. This article
will elaborate on the mechanisms, clinical features, assessment, and
management of fatigue and dyspnea, which are two of the most common
and often undertreated symptoms among cancer patients.
Fatigue
The National Comprehensive Cancer Network defines cancer-related
fatigue as =93a distressing, persistent, subjective sense of tiredness
or exhaustion related to cancer or cancer treatment that is not
proportional to recent activity and interferes with usual
functioning.=94 Fatigue is often severe among cancer patients; has an
identifiable anticipatory component; and results in general malaise,
lack of energy, diminished mental functioning, and lethargy, all of
which significantly impair quality of life. Fatigue can occur early
during the progression of the disease; may worsen due to treatment,
and can be found in almost all individuals with advanced cancer.
Sometimes, fatigue is referred to as tiredness, exhaustion, weakness,
lack of energy, and asthenia. However, these terms may have varying
implications for different patient populations. Further, different
studies on fatigue and dyspnea have focused on different outcomes,
which range from physical performance to just the subjective
sensation.
Mechanism
The mechanisms involved in cancer-related fatigue are not clearly
understood. It has been postulated that substances produced by the
tumor result in fatigue. When blood from a fatigued subject was
injected into a rested subject, it demonstrated manifestations of
fatigue. When cytokines are produced in the host in response to the
tumor, the same can also create a direct fatigue-inducing effect.
Other potential causes of chemotherapy- or radiotherapy-induced
fatigue include muscular or neuromuscular junction abnormalities.
Hence, it can be concluded that fatigue results from not just one, but
several different syndromes. In most patients with advanced cancer,
multiple mechanisms are responsible for causing fatigue.
Clinical Features
In an individual patient, there are often multiple causes of fatigue
with many interrelated factors.
Cachexia
A complex interaction of host and tumor products leads to cancer
cachexia. Host cytokines, for instance tumor necrosis factor,
interleukin-1 (IL-1), and IL-6 can potentially cause reduced food
consumption, loss of body weight, a reduction in synthesis of both
proteins and lipids, and increased lipolysis. Profound weakness and
fatigue can be caused by the metabolic abnormalities responsible for
the production of cachexia as well as the loss of muscle mass due to
progressive cachexia. However, there are several abnormalities that
can cause profound fatigue in patients who may not be experiencing
significant weight loss.
Immobility
Reduced physical activity has demonstrated to cause deconditioning and
diminished endurance to both physical exercise and routine daily
activities. In comparison, overexertion is often the cause of fatigue
among non-cancer patients. At risk are younger cancer patients
receiving aggressive antineoplastic treatments, for instance radiation
therapy and chemotherapy, and those who are making efforts to maintain
their professional and social activities.
Psychological distress
In case of non-cancer patients who experience fatigue, the final
diagnosis in around 75% of patients is psychological (for instance
anxiety, depression, and other types of psychological disorders). The
occurrence rate of major psychiatric disorders among cancer patients
is relatively low. Nonetheless, symptoms of adjustment disorders and
psychological distress with anxious or depressive moods are more
common. Fatigue is often the most prevalent symptom among patients
with a major depressive disorder or adjustment disorder.
Anemia
Low red blood cell count, if induced due to chemotherapy or advanced
cancer, has been linked with fatigue, and treatment of the same helps
improve symptoms of fatigue and quality of life among these patients.
However, treatment of anemia among terminally ill patients may not
help improve fatigue satisfactorily due to the multifactorial
characteristic of its etiology. Fatigue can also occur due to the
relatively more intense characteristics of other contributory factors.
Autonomic failure
Autonomic insufficiency is a medical complication that occurs
frequently among patients with advanced cancer. Instances of autonomic
failure have also been seen among patients with a specific type of
severe chronic fatigue syndrome. While the connection between fatigue
and autonomic dysfunction has not yet been established among cancer
patients, the same should be suspected among patients with signs of
autonomic failure including severe postural hypotension.
---------------------------------------------
Send posts to CO-CURE@listserv.nodak.edu
Unsubscribe at http://www.co-cure.org/unsub.htm
---------------------------------------------
Co-Cure's purpose is to provide information from across the spectrum of
opinion concerning medical, research and political aspects of ME/CFS and/or
FMS. We take no position on the validity of any specific scientific or
political opinion expressed in Co-Cure posts, and we urge readers to
research the various opinions available before assuming any one
interpretation is definitive. The Co-Cure website <www.co-cure.org> has a
link to our complete archive of posts as well as articles of central
importance to the issues of our community.
---------------------------------------------
