Exercise improves physical functioning, fatigue in breast cancer patients
Exercise and physical activity during and after treatment improve short-term self-reported physical functioning and fatigue in breast cancer patients, reports a new systemic review.
Randomized controlled trials (RCT) that investigated the effects of exercise interventions on female breast cancer patients who had received surgery were searched from the databases of PEDro, PsycINFO, AMED, CINAHL, Medline and EMBASE.
Taking into consideration the randomization procedure, allocation concealment, blinding, performance bias, loss to follow up and intention to treat, the methodological qualities of the studies were evaluated using the Norwegian Knowledge Centre for the Health Services handbook for systematic review.
Application of the selection criteria yielded 33 eligible studies, 25 of which were RCTs, corresponding to 3,418 nonmetastatic breast cancer patients at least 18 years of age. All patients had received chemotherapy, radiotherapy or both after surgery; most cases were early-stage breast cancers. [Breast 2017;33:166-177]
Only six trials were found to have few issues with the design and were defined to have high methodological quality. Blinding of the outcome evaluators was the most common limitation in the moderate studies. Moreover, different types of assessment tools to assess health-related quality of life (HRQoL) and fatigue across the different studies.
The efficacy of exercise intervention on physical functioning was investigated in 21 trials. Regardless of when the intervention was performed, and compared to controls, it resulted in a small but significant improvement in physical functioning (standard mean difference [SMD], 0.27; 95 percent CI, 0.13 to 0.42; p=0.0002).
Similarly, exercise intervention yielded significant physical function improvements when performed during (7 studies; SMD, 0.14; 0.01 to 0.27; p=0.03) and after (14 studies; SMD, 0.41; 0.19 to 0.63; p=0.0003) treatment.
The impact of exercise interventions on fatigue was explored in 17 RCTs. Independent of when it was administered, exercise significantly reduced fatigue in breast cancer patients (SMD, -0.32; -0.49 to -0.14; p=0.0006) compared to those who did not exercise.
Exercise interventions administered during (8 studies; SMD, -0.19; -0.31 to -0.07; p=0.002) and after (9 studies; SMD, -0.52; -0.96 to -0.09; p=0.02) treatment also significantly reduced fatigue relative to controls.
“This meta-analysis provides evidence that exercise programmes carried out either during or following adjuvant breast cancer treatment have a small but positive impact on physical functioning and cancer-related fatigue in breast cancer patients compared to conventional care,” the investigators wrote.
Moreover, the findings of the meta-analysis corroborate recently published studies which report that the benefits may slightly be more tangible if exercise interventions are initiated after therapy instead of during chemo- and/or radiotherapy.
Six-month follow-up information on physical function and fatigue were available in nine studies. Both physical functioning (SMD, 0.19; 0.05 to 0.33; p=0.007) and fatigue outcomes (SMD, -0.25; -0.44 to -0.07; p=0.008) were still significantly improved in patients that underwent exercise intervention compared to controls.
Because breast cancer patients tend to have long survival times after treatment, their long-term qualities of life are important metrics.
“Our findings showed that the patients that performed exercise show benefits 6 months later,” the investigators noted. “However, future studies should include even longer follow-up after the specific intervention to study the long-term effects of such interventions in breast cancer patients.”
In addition, “[f]uture large-scale randomized studies are needed to investigate the optimal exercise frequency, type, intensity and delivery in order to tailor exercise to individual breast cancer patients,” they added.