Researchers say fatigue is the most common and distressing problem facing cancer survivors after treatment with chemotherapy, radiation, or immune therapy. For many cancer patients, the feelings of persistent tiredness can be severe and drastically limit their daily activities.
The National Comprehensive Cancer Network (NCCN) describes cancer-related fatigue as an unusual, persistent, and subjective sense of tiredness related to cancer or cancer treatment that interferes with usual functions.
Previous studies have suggested that impaired immune systems or anemia (low levels of the red blood cells that carry oxygen) were associated with cancer-related fatigue. But in this study, researchers found these factors were unrelated to fatigue among a group of people treated for leukemia, lymphoma, and other blood-related cancers.
The findings appear in the July issue of the Annals of Oncology.
Cancer Fatigue Not Linked to Other Conditions
Researchers studied 71 people who were in remission from their blood-related cancers and had ended treatment at least three months before the study began.
The participants answered questionnaires about their mental status, health, and activities, and underwent physical and medical examinations.
Researchers found people who were depressed and had impaired physical function were much more likely to suffer from cancer-related fatigue. But there was no correlation between fatigue and other conditions, such as thyroid, liver, and kidney function, anemia, and immune system function, that might also lead to fatigue.
For example, those who had high scores on measures of fatigue had an average depression score that was 10 times higher than that of those who had low fatigue scores. Those who were very fatigued also had average physical performance scores that were five times lower than those reported by non-fatigued cancer patients.
Researchers say the relationship between reduced physical function and depression and their role in cancer-related fatigue merits further study.
"Impaired physical performance and depression seem to be critical components in cancer-related fatigue although we have not yet clarified the association between the two factors," says researcher Fernando Dimeo of the Charité University Medical Center in Berlin, Germany, in a news release.
"Impaired performance can result in increased dependence, lower self-esteem, reduced social activities, restricted family life, and a pessimistic mood," says Dimeo. "The patient can also interpret poor performance as a sign of poor health and this increases psychological distress.
"On the other hand, depressed and anxious patients are more likely to limit outdoor activities and resort to a passive lifestyle, which can result in loss of muscle condition and physical performance."
SOURCES: Dimeo, F. Annals of Oncology, July 19, 2004: vol 15: pp 1237-1242. News release, MW Communications.