Systematic review and meta-analysis of distance-based physical activity interventions for cancer survivors (2013-2018): We still haven't found what we're looking for

Background: Physically active cancer survivors have a reduced risk of cancer recurrence and mortality. Given the health advantages of active lifestyles in cancer survivorship, as well as the barriers preventing physical activity (e.g., geography, time) there is a need to develop and evaluate effective physical activity interventions that employ distance-based (i.e., non face-to-face) approaches. The primary objective of this study was to provide a systematic review and meta-analysis of present-day (2013-2018) distance-based physical activity behaviour change interventions for cancer survivors. Methods: PubMed and Embase databases were searched from November 2012 up to June 2018. Studies were included that met the following criteria: (1) written in English, (2) included adult cancer survivors (either undergoing or completed treatment), (3) was a controlled intervention study, and (4) the intervention was distance-based (delivered via distance) with no more than one face-to-face contact. Review Manager 5 (RevMan 5) software was used to perform a meta-analysis on all randomized controlled trials (RCTs) that presented self-reported or objectively measured physical activity post-intervention means and standard deviations. Risk of bias for each study was assessed using The Cochrane Risk of Bias Tool. Results: We included 29 RCTs. Across the 29 studies, the total number of participants in these studies was 5218. Median sample size was 95 and ranged from 19 to 463. Thirteen (45%) studies focused on breast cancer survivors and median months since diagnosis was 24 (range 6-79). Moderate-to-vigorous intensity physical activity data from 24 RCTs were included in the meta-analysis and indicated an overall small effect (standardized mean difference) of 0.21 (95% CI 0.11-0.32) favoring the interventions. Conclusions: Intervention effects on physical activity were small. Drawing conclusions from these trials remains challenging given major limitations of these trials included poor methodological design, small sample sizes, lack of statistical power, homogeneous samples (e.g., caucasian, young, well-educated), and poor measures of physical activity (e.g., self-report). Relying on the present landscape of distance-based programs aiming to facilitate physical activity among cancer survivors may not be prudent.