Randomized Trial Evaluating a Self-Guided Lifestyle Intervention Delivered via Evidence-Based Materials versus a Waitlist Group on Changes in Body Weight, Diet Quality, Physical Activity, and Quality of Life among Breast Cancer Survivors.

Background: Lifestyle interventions for breast cancer survivors have proved effective at stimulating positive behavior change and promoting healthy weight loss, although integrating these programs into clinical practice is challenging. We evaluated the effect of a 6-month, unsupervised, self-guided, lifestyle intervention using printed materials and online videos vs. waitlist group on body weight for breast cancer survivors. Methods: The Lifestyle, Exercise and Nutrition (LEAN) Self-Guided trial randomized breast cancer survivors with a body mass index ≥25 kg/m 2 to a 6-month lifestyle intervention (N = 102) or waitlist group (N = 103). Effects of the intervention on self-reported body weight, physical activity (PA), diet quality (via Health Eating Index-2010 (HEI-2010)), and quality of life were assessed using mixed model repeated measures analysis. Results: At 6 months, the intervention arm had significantly greater weight loss compared with the waitlist group (mean difference = -1.3 kg, 95% confidence interval [CI] = -2.5, -0.13). We observed suggestive improvements in PA (mean difference = 18.7 min/week, 95% CI = -24.2, 61.6), diet quality (mean difference in HEI = 3.2 points, 95% CI = -0.20, 6.5), and fatigue (mean difference in Functional Assessment of Chronic Illness Therapy-Fatigue scale = 1.4 points, 95% CI = -1.1, 3.9). Conclusions: The LEAN Self-Guided intervention led to favorable weight changes over 6 months. Low-resource-intensive programs have the potential to be delivered in diverse healthcare settings and may support breast cancer survivors in achieving a healthy body weight.