April 28, 2008 — Physical exercise can help reduce fatigue both during and after treatment of cancer, but evidence is limited to suggest the best type or optimal intensity of exercise in this setting, according to the results of a review reported in the April 16 issue of the Cochrane Database of Systematic Reviews.

"Cancer-related fatigue is now recognised as an important symptom associated with cancer and its treatment," write Dr. Fiona Cramp and Dr. J . Daniel from the University of the West of England in Bristol, United Kingdom. "A number of studies have investigated the effects of physical activity in reducing cancer-related fatigue with no definitive conclusions regarding its effectiveness."

The goal of this review was to examine the impact of exercise on cancer-related fatigue, both during and after cancer treatment.

Using key words, the reviewers searched The Cochrane Controlled Trials Register (CENTRAL/CCTR), MEDLINE (1966 to July 2007), EMBASE (1980 to July 2007), CINAHL (1982 to July 2007), the British Nursing Index (January 1984 to July 2007), AMED (1985 to July 2007), SIGLE (1980 to July 2007), and Dissertation Abstracts International (1861 to July 2007) as well as reference lists of identified articles and pertinent reviews. The investigators also hand searched relevant journals and contacted experts in the field of cancer-related fatigue.

Criteria for inclusion in the review were randomized controlled trials (RCTs) that studied the effect of exercise on cancer-related fatigue in adults. Two reviewers independently evaluated the methodologic quality of studies and extracted data using predefined criteria. Wherever possible and based on available data, the reviewers performed meta-analyses for fatigue using a random-effects model.

Of 28 included studies enrolling a total of 2083 participants, 16 were of patients with breast cancer, and these 16 studies enrolled a total of 1172 participants. The meta-analysis of all fatigue data included 22 comparisons of data from 920 participants randomized to receive an exercise intervention and from 742 control participants.

After the intervention, exercise was statistically more effective than the control intervention (standardized mean difference [SMD], –0.23; 95% confidence interval [CI], –0.33 to –0.13).

"Exercise can be regarded as beneficial for individuals with cancer-related fatigue during and post cancer therapy," the study authors write. "Further research is required to determine the optimal type, intensity and timing of an exercise intervention."

Limitations of the review were the diversity of studies, small sample size in some studies, considerable clinical heterogeneity between studies, moderate statistical heterogeneity for the total fatigue (P = .009; I² = 46.7%) and the breast cancer fatigue (P = .02; I² = 48.9%) meta-analyses, all studies identified published in English, and data not available for meta-analysis for all identified studies meeting inclusion criteria.

"Exercise appears to have some benefit in the management of fatigue both during and after cancer treatment," the reviewers conclude. "Therefore it should be considered as one component of the management strategy for fatigue that may include a range of other interventions and education. . . . Further work is necessary to determine the most effective parameters of exercise for fatigue management including the types of exercise (aerobic and resistance), mode of exercise, frequency and length of sessions, and intensity of exercise carried out."

This review received internal support from the Faculty of Health and Social Care, University of the West of England United Kingdom. The reviewers have disclosed no relevant financial relationships.

Cochrane Database Syst Rev. Published online April 16, 2008.

Clinical Context

Study Highlights

• RCTs evaluating the effect of exercise on cancer-related fatigue in any sex, tumor type, stage, and treatment with outcomes of patient-reported fatigue, time exercising, attrition, aerobic capacity, quality of life, anxiety, and depression were included.
• Databases searched included the Cochrane, MEDLINE, EMBASE, CINAHL, the British Nursing Index, AMED, SIGLE, and the Dissertation Abstracts International.
• Fatigue had to be included as an outcome, and the number of participants with a 50% reduction in fatigue and fatigue scores were reported in the analysis.
• 2 independent reviewers assessed methodologic quality using the Oxford Quality Scale.
• 28 articles qualified for inclusion.
• 19 studies involved specific cancer diagnoses, and 9 included a range of diagnoses.
• The majority of diagnoses were for breast cancer.
• Mean age of the participants was 39 to 69 years, with most in the fifth decade of life.
• 16 studies included women only, 10 included both men and women, and 2 included men only.
• Mode, intensity, duration, and timing of exercise varied across studies.
• 13 studies examined home-based exercises, 16 supervised institution-based exercises, and some encouraged both forms of these exercises.
• 7 studies prescribed walking, 4 prescribed stationary biking, and 13 offered a range of modalities.
• 3 studies included strength training, 2 included resistance training, and 2 included flexibility training, with 2 involving yoga.
• Intensity was monitored by the Borg scale and self-ratings and varied across studies.
• Frequency and duration varied from twice per week to daily for 10 to 75 minutes.
• The intervention period ranged from 3 to 32 weeks.
• The comparison group was usual care or no exercise in 16 studies, and other control interventions included relaxation training, stretching, tai chi, and group psychotherapy.
• Fatigue was assessed by a variety of validated instruments such as the Functional Assessment of Cancer Therapy-Fatigue Scale and the fatigue subscale of the Profile of Mood States.
• Other measures included aerobic capacity, quality of life, body composition, physical activity, mood, depression, and anxiety.
• 10 studies recruited less than 40 participants, 8 studies did not provide adherence data, and only 5 did not report dropout rate.
• Long-term follow-up was poor.
• Of 28 studies with 2083 participants, a meta-analysis was performed on 22 comparisons, with data for 920 who received exercise and 742 who received the control intervention.
• Exercise was statistically more effective than control for posttest scores (SMD, –0.23; 95% CI, –0.33 to –0.13).
• A similar result was found for mean change scores from pretest to posttest.
• The exercise intervention was more effective than control intervention, both during and after cancer treatment.
• For all patients with breast cancer, the exercise intervention was statistically more effective than the control intervention.
• For prostate cancer, 1 study showed an effect and the other did not.
• No statistical difference was seen for exercise for single studies on colorectal cancer, lymphoma, and multiple myeloma.
• Mixed results were obtained for aerobic capacity, quality of life, anxiety, and depression, with some studies showing a positive effect of exercise and others not showing an effect.
• No effect was found for self-efficacy.

Pearls for Practice

• Exercise of varying duration, intensity, and type is effective in reducing cancer-related fatigue.
• The effect of exercise is greatest in patients with breast cancer and is seen during and after treatment, with variable impact on quality of life, aerobic capacity, and mood.

CME Test