Effects of exercise interventions on cancer-related fatigue in breast cancer patients: an overview of systematic reviews.

Objective: This overview of systematic reviews aims to critically appraise and consolidate evidence from current systematic reviews (SRs)/meta-analyses on the effects of exercise interventions on cancer-related fatigue (CRF) in breast cancer patients.

Methods: SRs/meta-analyses that explored the effects of exercise interventions on CRF in breast cancer patients compared with the routine methods of treatment and care were retrieved from nine databases. The methodological quality of the included SRs was appraised using A MeaSurement Tool to Assess systematic Reviews II (AMSTAR II). The Grading of Recommendations Assessment, Development and Evaluation (GRADE) was used to calculate the grading of outcomes in the included SRs. The exercise type, frequency, duration, and inclusion/absence of supervision were further evaluated with subgroup analyses. The Stata 16.0 software was utilized for data analysis.

Results: Twenty-nine reviews were included. The overall methodological quality and level of evidence of the included reviews were unsatisfactory, with only three reviews rated as high methodological quality and no review identified as high-quality evidence. Moderate certainty evidence indicated that exercise could improve fatigue in breast cancer patients (SMD = - 0.40 [95%CI - 0.58, - 0.22]; P = 0.0001). Subgroup analysis based on the types of exercise showed that yoga (SMD = - 0.30 [95%CI - 0.56, - 0.05]; I = 28.7%) and aerobic exercise (SMD = - 0.29 [95%CI - 0.56, - 0.02]; I = 16%) had a significantly better effect on CRF in breast cancer patients; exercising for over 6 months (SMD = - 0.88 [95%CI - 1.59, - 0.17]; I = 42.7%; P = 0.0001), three times per week (SMD = - 0.77 [95%CI - 1.04, - 0.05]; I = 0%; P = 0.0001), and for 30 to 60 min per session (SMD = - 0.81 [95%CI - 1.15, - 0.47]; I = 42.3%; P = 0.0001) can contribute to a moderate improvement of CRF. Supervised exercise (SMD = - 0.48 [95%CI - 0.77, - 0.18]; I = 87%; P = 0.001) was shown to relieve CRF.

Conclusion: Exercise played a favorable role in alleviating CRF in breast cancer. Yoga was recommended as a promising exercise modality for CRF management in the majority of the included studies. Exercising for at least three times per week with 30 to 60 min per session could be recommended as a suitable dosage for achieving improvement in CRF. Supervised exercise was found to be more effective in alleviating CRF than unsupervised exercise. More rigorously designed clinical studies are needed to specify the exact exercise type, duration, frequency, and intensity to have an optimal effect on CRF in breast cancer patients.

Trial Registration: ClinicalTrials.gov Identifier: CRD42020219866.