Effect of Exercise on Sarcopenia among Cancer Survivors: A Systematic Review

SIMPLE SUMMARY: Sarcopenia is a condition characterized by loss of skeletal muscle mass and low muscle strength or physical performance. Cancer survivors are likely to be impacted by sarcopenia and suffer from a worse prognosis. Exercise has been suggested to be a promising tool to attenuate sarcopenia, but its effect among cancer survivors has not been systematically tested yet. We conducted a systematic review of seven interventional studies examining the effects of exercise on sarcopenia among cancer survivors. Results suggested that exercise improved muscle quantity and potentially reversed sarcopenia among breast, gastric, prostate and liver cancer survivors. If the relationship is further supported by larger trials, we could potentially identify cancer survivors at higher risk of adverse health outcomes by screening for sarcopenia and improve their prognosis and quality of life through exercise interventions. ABSTRACT: Sarcopenia is related to adverse health outcomes in cancer survivors. Previous reviews reported exercise improved muscle mass or function in cancer survivors, but thus far a systematic review examining the effect of exercise on sarcopenia in this population has not been conducted. Therefore, we systematically searched PubMed, CENTRAL (Cochrane Central Register of Controlled Trials) and ClinicalTrials.gov for publications and ongoing trials (through November 2021) that reported exercise interventions and diagnosed sarcopenia among cancer survivors. Seven exercise trials were eligible for this review. Six of seven studies showed exercise increased skeletal muscle post intervention (1.6% to 5.4% increase within intervention groups compared to baseline, p ≤ 0.07; 2.1% to 12.8% greater increase for intervention than control groups, p ≤ 0.02) and in the three studies that reported sarcopenia reversal, an improvement (18.2% to 42.9% decrease in sarcopenia in exercise groups, 5.2% increase to 16.7% decrease in sarcopenia in control groups, p = 0.04) was observed. Existing research indicates the potential for exercise to improve health outcomes for cancer survivors through building muscle and attenuating sarcopenia. More high-quality, long-term, large randomized controlled trials examining effects of different exercise types and doses to improve sarcopenia should be conducted to further explore this important topic.