Efficacy of Exercise Therapy on Cardiorespiratory Fitness in Patients With Cancer: A Systematic Review and Meta-Analysis

<jats:sec><jats:title>Purpose</jats:title><jats:p> To evaluate the effects of exercise therapy on cardiorespiratory fitness (CRF) in randomized controlled trials (RCTs) among patients with adult-onset cancer. Secondary objectives were to evaluate treatment effect modifiers, safety, and fidelity. </jats:p></jats:sec><jats:sec><jats:title>Methods</jats:title><jats:p> A systematic search of PubMed, Embase, Cumulative Index to Nursing and Allied Health Literature, and the Cochrane Library was conducted to identify RCTs that compared exercise therapy to a nonexercise control group. The primary end point was change in CRF as evaluated by peak oxygen consumption (VO<jats:sub>2peak</jats:sub>; in mL O<jats:sub>2</jats:sub> × kg<jats:sup>−1</jats:sup> × min<jats:sup>−1</jats:sup>) from baseline to postintervention. Subgroup analyses evaluated whether treatment effects differed as a function of exercise prescription (ie, modality, schedule, length, supervision), study characteristics (ie, intervention timing, primary cancer site), and publication year. Safety was defined as report of any adverse event (AE); fidelity was evaluated by rates of attendance, adherence, and loss to follow-up. </jats:p></jats:sec><jats:sec><jats:title>Results</jats:title><jats:p> Forty-eight unique RCTs that represented 3,632 patients (mean standard deviation age, 55 ± 7.5 years; 68% women); 1,990 (55%) and 1,642 (45%) allocated to exercise therapy and control/usual care groups, respectively, were evaluated. Exercise therapy was associated with a significant increase in CRF (+2.80 mL O<jats:sub>2</jats:sub> × kg<jats:sup>−1</jats:sup> × min<jats:sup>−1</jats:sup>) compared with no change (+0.02 mL O<jats:sub>2</jats:sub> × kg<jats:sup>−1</jats:sup> × min<jats:sup>−1</jats:sup>) in the control group (weighted mean differences, +2.13 mL O<jats:sub>2</jats:sub> × kg<jats:sup>−1</jats:sup> × min<jats:sup>−1</jats:sup>; 95% CI, 1.58 to 2.67; I<jats:sup>2</jats:sup>, 20.6; P < .001). No statistical significant differences were observed on the basis of any treatment effect modifiers. Thirty trials (63%) monitored AEs; a total of 44 AEs were reported. The mean standard deviation loss to follow-up, attendance, and adherence rates were 11% ± 13%, 84% ± 12%, and 88% ± 32%, respectively. </jats:p></jats:sec><jats:sec><jats:title>Conclusion</jats:title><jats:p> Exercise therapy is an effective adjunctive therapy to improve CRF in patients with cancer. Our findings support the recommendation of exercise therapy for patients with adult-onset cancer. </jats:p></jats:sec>