Frequency, severity, clinical course, and correlates of fatigue in 372 patients during 5 weeks of radiotherapy for cancer.

BACKGROUND: Patients often describe fatigue as the most distressing of the symptoms they experienced during their cancer treatment. Fatigue may increase from initial levels experienced during cancer treatment with the addition of radiotherapy (RT).
METHODS: Three hundred seventy-two patients completed a Symptom Inventory at the initiation of RT and weekly for 4 weeks thereafter. Descriptive statistics were used to evaluate differences in fatigue at baseline by demographics and diagnosis. Changes over the course of treatment were evaluated by repeated-measures analysis of variance and Student t tests for paired data. The effect of diagnosis, age, gender, and previous treatment on fatigue was investigated by linear and hierarchical regression.
RESULTS: Fifty-seven percent of patients reported some degree of fatigue at the initiation of RT. The proportion increased to 76% by Week 3 and then to 78% at Week 5. Eighty-four percent of patients with initial fatigue remained fatigued throughout the 5-week course. Of the 160 patients without initial fatigue, 70% subsequently developed it. By Week 5, only 13% of patients had never reported any fatigue. Severity was found to be related to diagnosis, with patients with prostate carcinoma reporting the least severe fatigue and patients with lung, alimentary, and head and neck carcinoma reporting the most severe fatigue. Neither gender, age, nor total dose of RT predicted significant variance in severity.
CONCLUSIONS: Fatigue was a common adverse effect of RT for cancer, reported by more than three-fourths of patients by the third to fifth weeks of treatment. Cancer diagnosis was the only factor found to be significantly related to variation in fatigue severity. Additional studies should be devised to identify other underlying causes of RT-related fatigue. Copyright 2005 American Cancer Society