Effects of exercise in patients treated with stem cell transplantation for a hematologic malignancy: a systematic review and meta-analysis.

We performed a systematic review and meta-analysis evaluating the effectiveness of exercise interventions compared with usual care on physical fitness, fatigue and health-related quality of life in patients with hematologic malignancies treated with stem cell transplantation. Electronic databases were searched up to June 2012. We included randomized controlled trials comparing exercise with usual care, in which at least 75% of the patients had a hematologic malignancy. Standard mean differences were calculated and pooled to generate summary effect sizes (ES) and 95% confidence intervals (CI). The Cochrane Collaboration Risk of Bias Tool was used to assess the methodological quality of the studies. Eight studies met our inclusion criteria. Exercise had a statistically significant moderately favourable effect on cardiorespiratory fitness (ES=0.53, 95% CI=0.13-0.94), lower extremity muscle strength (ES=0.56, 95% CI=0.18-0.94) and fatigue (ES=0.53, 95% CI=0.27-0.79). Significant small positive effects were found for upper extremity muscle strength, global quality of life, and physical, emotional and cognitive functioning. In conclusion, exercise seems to have beneficial effects in patients treated with stem cell transplantation. However, all studies had at least some risk of bias, and for cardiorespiratory fitness and lower extremity muscle strength substantial heterogeneity in effect sizes were observed. Further high quality research is needed to determine the optimal exercise intervention and clinical implications.