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

PurposeTo 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.MethodsA 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 (VO2peak; in mL O-2 x kg(-1) x min(-1)) 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.ResultsForty-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-2 x kg(-1) x min(-1)) compared with no change (+0.02 mL O-2 x kg(-1) x min(-1)) in the control group (weighted mean differences, +2.13 mL O-2 x kg(-1) x min(-1); 95% CI, 1.58 to 2.67; I-2, 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.ConclusionExercise 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.