Effectiveness of an exercise intervention on cognition in breast cancer survivors: a randomized controlled trial.

BACKGROUND: Cognitive problems are common after breast cancer, yet few randomized controlled trials have evaluated interventions to address them. This study tested whether a 12-month exercise intervention improved cognition in breast cancer survivors. METHODS: Breast cancer survivors (n = 253) were randomized to an exercise arm with a remotely delivered intervention or a Health & Wellness arm receiving calls on healthy aging topics at the same frequency. The 6-month intervention (primary end-point) was followed by a 6-month maintenance phase (secondary end-point). At baseline, 3, 6, and 12 months, participants wore an accelerometer and completed the PROMIS Cognitive Abilities Questionnaire, the NIH Toolbox Digit symbol test (Processing Speed), and a neurocognitive battery assessing memory, executive function, and attention. Linear mixed models compared outcomes between arms. RESULTS: The Exercise arm had greater increases in moderate to vigorous physical activity (18 minutes/day baseline, 23.5 minutes/day 12 months) than the Health & Wellness arm (15 minutes/day baseline, 15.5 minutes/day 12 months) at all follow-ups (P-values < .01). No significant between-group effects were observed for primary outcomes of self-reported cognition or processing speed at 6 or 12 months (P-values > .05). However, for secondary outcomes, the Exercise arm had greater improvements than the Health & Wellness arm in attention (6 months: b = 0.14, P = 0.03; 12 months: b = 0.21, P=.002), and memory (6 months: b = 0.18, P < .01). CONCLUSION: A remotely delivered Exercise intervention was not superior to a Health & Wellness intervention for self-reported cognition or processing speed. However, secondary outcomes suggest sustained improvements in attention and short-term benefits in memory. Exercise warrants further investigation as a strategy to support cognitive health in breast cancer survivors. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT04049695.