The quality of evidence is downgraded by study quality (no blinding of outcome assessment, unclear allocation concealment).
A systematic review and meta-analysis «Wilson OWA, Matthews CE, Wojcik KM, et al. The Effects of Post-diagnosis Recreational Aerobic Exercise among Breast Cancer Survivors: A Systematic Review/Meta-Analysis. Cancer Epidemiol Biomarkers Pre»4 included 20 studies assessing the effects of post-diagnosis recreational aerobic exercise among breast cancer survivors. Less than half of participants (44%, n=50 689) met aerobic exercise guidelines for health (≥ 2.5 hours/week). Meeting guidelines was associated with a about 50% reduction in the hazard ratio (HR) for all-cause mortality, with further reductions up to 4.5 hours/week. Compared with no/minimal exercise (< 45 min/week), some exercise (≥ 45 to <150 min/week; HR 0.72; 95% CI 0.62 to 0.83) and meeting exercise recommendations for health (≥ 150 min/week; HR 0.60; 95% CI 0.51 to 0.70) were associated with a lower risk of all-cause mortality.
A Cochrane review «Markes M, Brockow T, Resch KL. Exercise for women receiving adjuvant therapy for breast cancer. Cochrane Database Syst Rev 2006 Oct 18;(4):CD005001 [Assessed as up-to-date: 30 March 2015]. »1 (abstract «»1, review «Exercise for women receiving adjuvant therapy for breast cancer»2) included 32 trials involving a total of 2626 women. Physical exercise (aerobic or resistance exercise or both) during adjuvant treatment for breast cancer improved physical fitness (SMD 0.42, 95% CI 0.25 to 0.59, 15 trials, n=13100; moderate-quality evidence) and, slightly reduced fatigue (SMD -0.28, 95% CI -0.41 to -0.16; 19 trials; n=1698; moderate-quality evidence) compared to non-exercising control groups. Exercise showed non-significant improvement in cancer site-specific quality of life (MD 4.24, 95% CI -1.81 to 10.29; 4 studies; n=262), and in depression (SMD -0.15, 95% CI -0.30 to 0.01; 5 studies; n=674).
Another Cochrane review «Lahart IM, Metsios GS, Nevill AM et al. Physical activity for women with breast cancer after adjuvant therapy. Cochrane Database Syst Rev 2018;(1):CD011292. »2 (abstract «»3, review «Exercise for women receiving adjuvant therapy for breast cancer»2) included 63 trials involving a total of 5761 women with breast cancer. Compared to control, physical activity interventions (aerobic exercise and/or resistance training) resulted in small-to-moderate improvements in HRQoL (health related quality of life), emotional function, perceived physical function, anxiety, and cardiorespiratory fitness (table «Physical activity versus control for women with breast cancer after adjuvant therapy (immediate postintervention)»1). Small improvements sustained for 3 months or longer postintervention in fatigue, cardiorespiratory fitness, and self-reported physical activity.
| Outcome (follow-up: median 12 weeks) | Assumed risk - Control | Risk with intervention - Physical activity (95% CI) | No. of participants (studies) Quality of evidence |
|---|---|---|---|
| HRQoL using FACT-G (0 to 104 scale) | -2.70 to 2.72 standard deviation units (SD) | 0.39 SD higher (0.21 to 0.57 higher); FACT-points: 5.9 (3.2 to 8.6) points higher | 1996 (22) Low |
| Perceived physical function using FACT-PBW (0 to 28 scale) | -2.64 to 1.64 SD | 0.33 SD higher (0.18 to 0.49 higher); FACT-points: 1.7 (0.9 to 2.5) points higher | 2129 (25) Moderate |
| Anxiety using PROMIS (0 to 9 scale) | -1.33 to 1.19 SD | 0.57 SD lower (0.95 to 0.19 lower); PROMIS-points: 1.9 (3.2 to 0.6) points lower | 326 (7) Very low |
| Depression using FACT-F (0 to 52 scale) | -0.79 to 2.84 SD | 0.34 SD lower (0.62 to 0.05 lower); FACT-points: 2.8 (4.1 to 1.6) points lower | 657 (12) Low |
| Fatigue using FACT-F (0 to 52 scale) | -1.83 to 1.69 SD | 0.32 SD lower (0.47 to 0.18 lower); FACT-points 2.8 (4.1 to 1.6) points lower | 2020 (26) Moderate |
| Cardiorespiratory fitness: VO2max (mL/kg/min) | 0.51 to 3.59 SD | 0.44 SD higher (0.30 to 0.58 higher); VO2max 2.1 (1.4 to 2.7) mL/kg/min higher | 1265 (23) Moderate |
A meta-analysis «Yuan Y, Lin L, Zhang N et al. Effects of Home-Based Walking on Cancer-Related Fatigue in Patients With Breast Cancer: A Meta-analysis of Randomized Controlled Trials. Arch Phys Med Rehabil 2021;():. »3 assessing home-based walking on cancer-related fatigue included 8 RCTs with a total of 764 patients receiving anticancer treatment. Walking decreased fatigue (SMD=-0.61; 95% CI -0.86 to -0.36; P<.001); walking for a gradually increased duration (SMD=-1.24; 95% CI -2.20 to -0.28; P=.010), and no restrictions on walking intensity (SMD=-1.03; 95% CI, -1.75 to -0.31; P=.005).