A Cochrane review included 28 studies with a total of 2 083 subjects. The majority of participants had breast cancer (n = 16 studies; n = 1 172 participants). A meta-analysis of all fatigue data, incorporating 22 comparisons provided data for 920 participants who received an exercise intervention and 742 control participants. 13 studies investigated home based/unsupervised exercise programmes whereas 16 studies investigated supervised, institutional based exercise programmes. The intervention period varied greatly between studies with a range from three weeks to 32 weeks At the end of the intervention period exercise was statistically more effective than the control intervention (SMD -0.23, 95% CI -0.33 to -0.13).
Comment: The quality of evidence is downgraded by inconsistency (heterogeneity in interventions and outcomes) and by indirectness (limited data on other cancers than breast cancer).