The Physician Data Query Supportive Care file contains full-text cancer information designed especially for health care professionals. Records contain information and explanations about the common complications and side effects of cancer therapy. An editorial board of oncology nurse specialists meets regularly to review and update the information in PDQS.
PDQS contains full-text documents, each devoted to a particular topic of supportive care.
The following alphabetical list provides the two-letter label, the relevant alias, and an example for each PDQ-Supportive Care File-Full Text database field.
===== ============ Label Name/Example ===== ============ an Accession Number [Word and Phrase Indexed] example 1: PDQS-000004.an. example 2: 000004.an. cn Cancer Name [Word and Phrase Indexed] example 1: fatigue.cn. example 2: fatigue intervention.cn. ss Summary Statement [Word Indexed] example: balanced diet.ss. up Update Code [Phrase Indexed] example: 9703.up.
AHCPR Guides Sentence Syntax: limit 1 to ahcpr guides
Command Syntax: ..c/pdqs Sentence Syntax: use pdqs
Accession Number
PDQS-000004
Update Code
9703
Cancer Name
Fatigue: fatigue factors
Summary Statement
Although a variety of treatment- and disease-related factors may
contribute to the development of fatigue, the exact mechanisms of
chronic fatigue in oncology patients are unknown.
Fatigue is a common prodrome of disease progression and is
frequently one of the presenting signs for both pediatric and adult
malignancies.[1] A common complaint given by parents of a child
diagnosed with acute lymphocytic leukemia or non-Hodgkin's lymphoma
is a history of excessive fatigue accompanied by paleness for up to
6 weeks. Tumors can influence fatigue indirectly as well as by
infiltrating the bone marrow, causing anemia, and by producing toxic
metabolic substances that interfere with normal cellular processes.
Marked increases in Cori cycle activity leading to excess lactate
and hydrogen ion production have been reported in cancer
patients.[2-4] Accumulation of these substances may produce fatigue
by decreasing muscle contractility. Various models have been
proposed as explanations for the study of fatigue. Prolonged stress
producing a stress response is utilized by Aistar as a model for
fatigue.[5] Cancer patients frequently suffer from extreme stress
over a long period of time, causing them to expend energy manifested
by a high level of fatigue. In contrast, Kaempfer demonstrated that
energy requirements vary in cancer patients.[6] This suggests that
factors other than energy requirements are functioning to produce
fatigue.
A neurophysiological model has been proposed, composed of both
central and peripheral components. The central component consists
of psyche/brain and spinal cord. The peripheral system consists of
peripheral nerves, muscle sarcolemma, transverse tubular system,
calcium release, actin/myosin interaction, cross-bridge tension and
heat, and force/power output. Impairment of central components
causes lack of motivation, impaired spinal cord transmission, and
exhaustion or malfunction of brain cells in the hypothalamic
region. Damage to the peripheral component can cause impaired
peripheral nerve function in transmission at the neuromuscular
junction, thereby affecting fiber activation. Both are said to play
a role in chronic fatigue. The central mechanism may be the key to
explaining the extreme fatigue of biotherapy- treated patients.[7]
It remains to be established whether potentially neurotoxic
chemotherapeutic regimens cause fatigue through this mechanism.
Additionally, many oncology patients may be concurrently receiving
analgesics, hypnotics, antidepressants, antiemetics, or
anticonvulsants. Because many of these drugs exert their effect on
the central nervous system, they can significantly compound the
problem of fatigue.
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References:
1. Waskerwitz MJ, Leonard M: Early detection of malignancy: from
birth to twenty years. Oncology Nursing Forum 13(1): 50-57, 1986.
2. Burt ME, Aoki TT, Gorschboth CM, et al.: Peripheral tissue
metabolism in cancer-bearing man. Annals of Surgery 198(6):
685-691, 1983.
3. Gold J: Cancer cachexia and gluconeogenesis. Annals of the New
York Academy of Sciences 230: 103-110, 1974.
4. Nakamaru Y, Schwartz A: The influence of hydrogen ion
concentration on calcium binding and release by skeletal muscle
sarcoplasmic reticulum. Journal of General Physiology 59(1): 22-32,
1972.
-sample text truncated-
Some material in the PDQ database is from copyrighted publications of the respective copyright claimants. Users of the database are referred to the publication data appearing in the bibliographic citations, as well as to the copyright notices appearing in the original publication, all of which are hereby incorporated by reference. The NCI represents that PDQ is formulated with a reasonable standard of care. Except for this representation, NCI makes no representations or warranties, express or implied, including any implied warranty of merchantability or fitness for a particular purpose, with respect to PDQ. The documents contained in PDQ may be retained for personal or educational use only. Information should not be edited or modified. Any resale or redistribution of all or portions of the information is not permitted.
Because use of the PDQ database for insurance reimbursement decisions is contrary to the nature of the database, which is designed as a research tool and not to reflect all possible treatment options, customers agree to not make the database available to users who wish to use it for reimbursement decision purposes.
Revised 31 March, 1997