Effect of exercise training on peak oxygen consumption in patients with cancer: A meta-analysis

Background. We conducted a meta-analysis to determine the effects of supervised exercise training on peak oxygen consumption (VO_2peak) in adults with cancer. Methods. A literature review using Ovid MEDLINE (1950-2010), the Cochrane Central Register of Controlled Trials (1991-2010), AMED (1985-2010), Embase (1988-2010), PubMed (1966-2010), Scopus (1950-2010), and Web of Science (1950-2010) was performed to identify randomized controlled trials examining the effects of supervised exercise training on measurement of VO_2peak (via gas exchange analysis) in adults with cancer. Studies were selected using predetermined criteria, and two independent reviewers extracted data. Weighted mean differences (WMDs) were calculated using random effect models. Results. Six studies evaluated VO_2peak involving a total of 571 adult cancer patients (exercise, n-344; usual care control, n- 227). Pooled data indicated that exercise training was associated with a statistically significant increase in VO_2peak (WMD, 2.90 ml·kg^-1·min^-1; 95% confidence interval [CI], 1.16-4.64); however, significant heterogeneity was evident in this estimate (I², 87%). Usual care (control) was associated with a significant decline in VO_2peak from baseline to post intervention (WMD,-1.02 ml·kg^-1·min^-1; 95% CI,-1.46 to-0.58; I², 22%). Sensitivity analyses indicated superior improvements in VO_2peak for studies conducted for a shorter duration (<4 months) and following the completion of adjuvant therapy (p-values <.001). Exercise training was not associated with a higher incidence of adverse events, although safety was not rigorously monitored or reported. Conclusions. Supervised exercise training is associated with significant improvements in VO_2peak following a diagnosis of early-stage cancer, with minimal adverse events.