Mobile Phone Messaging-Based Interventions to Improve Physical Activity in Patients With Cancer: Systematic Review and Meta-Analysis.

Background: Despite the benefits of physical activity (PA) for improving cancer-related outcomes, the majority of patients with cancer fail to meet PA guidelines. Mobile phone messaging is a scalable approach for promoting PA, but its effect on improving PA among patients with cancer has not been reviewed. Objective: This review aims to systematically evaluate the effects of mobile phone messaging-based interventions in promoting PA among patients with cancer. Methods: A systematic search in 8 English and Chinese databases (PubMed, EMBASE, Web of Science, MEDLINE, the Cochrane Library, Scopus, Wanfang, and China National Knowledge Infrastructure) was performed. Randomized controlled trials that examined the effect of mobile phone messaging-based interventions on improving PA among patients with cancer were included. Potential sources of substantial heterogeneity were investigated by subgroup analysis based on participants' characteristics, mobile phone messaging regimens, and PA estimates. Random effects models were used to estimate the overall effect size. Risk of bias was assessed by 2 independent reviewers using the revised Cochrane Collaboration's risk of bias tool. Sensitivity analyses were performed through leave-one-out analyses, removal of outliers, and inclusion of only studies with low or some risk of bias. Potential publication bias was explored. Results: A total of 13 studies involving 777 individuals were included in this review. After intervention, mobile phone messaging-based interventions significantly improved objective PA with a small effect size (standardized mean difference [SMD]=0.37, 95% CI 0.10-0.64; P=.007; I2=0%), but not self-reported PA (SMD=0.20, 95% CI -0.07 to 0.47; P=.15; I2=56%) or step count (SMD=0.27, 95% CI -0.19 to 0.73; P=.25; I2=69%). Interventions that adopted more behavior change techniques and targeted patients who have completed active cancer treatment significantly improved step count. At follow-up, the effect of mobile phone messaging on self-reported PA, objective PA, and step count was found to be insignificant. Nine studies showed low or some risk of bias. Sensitivity analyses and trim-and-fill tests confirmed relatively stable effects of mobile phone messaging. No potential publication bias was identified. Conclusions: Mobile phone messaging-based interventions show promise as a scalable intervention to modestly improve objective PA in patients with cancer, though effects vary, with limited impact on self-reported PA or step count. Evidence for sustained long-term benefit remains limited, highlighting the need for rigorously designed trials with extended follow-up.