Effects of Aerobic Exercise Modality on Cognitive Outcomes among Breast Cancer Survivors

Abstract

Breast cancer has relatively high incidence and high survival rates, demonstrating that there is an ever-increasing population of survivors in the United States. These women frequently suffer from ongoing cognitive dysfunction, which hinders memory, work performance, and ability to complete activities of daily living. Exercise has been shown to improve results on objective cognitive tests in several clinical populations, but this has not been studied among recent breast cancer survivors. PURPOSE: This study was conducted to determine whether aerobic exercise is an effective intervention for improving cognition among recent breast cancer survivors. METHODS: Twenty breast cancer survivors who completed their primary treatment in the past 3 months were randomly assigned to 12 weeks of an aerobic exercise intervention (INT) or a sedentary control group (CON). The intervention group attended moderately intense exercise classes, 3 days each week, while the control group maintained their normal, inactive lifestyle. All participants completed pre/post cognitive testing utilizing the Trail Making Test (TMT-A), Controlled Oral Word Association Test (COWAT), and Design Fluency Trials 1-3 (DF1, DF2, DF3). Data was analyzed with repeated measures ANOVA. RESULTS: Executive function increased in INT vs. CON on scaled scores (SS) from DF1 (CON 11.71±3.5 vs. 10.86±3.0; INT 11.69±4.3 vs. 13.92±3.7, p=0.44). There was also a trend toward greater improvement in INT vs. CON on DF1+DF2 SS (CON 11.29±2.6 vs. 11.57±2.6; INT 12.23±3.4 vs. 14.38±3.4, p=0.178) and on DF1+DF2+DF3 SS (CON 11.43±2.4 vs. 11.86±2.7; INT 12.46±3.3 vs. 13.92±3.3, p=0.364). Education adjusted scores of attention and processing speed on TMT-A did not improve significantly in either group, but showed a slight trend toward greater speed in INT vs. CON (CON 25.12±8.6 vs. 24.39±9.8; INT 25.49±7.5 vs. 22.28±5.5, p=0.459). COWAT scores of verbal fluency did not appear to be affected by aerobic exercise (CON 37.43±14.8 vs. 36.43±15.8; INT 47.69±16.5 vs. 51.46±18.3, p=0.264). CONCLUSIONS: Aerobic exercise can improve several domains of cognitive function in breast cancer survivors when compared to usual care. Given a longer time-frame and larger sample size, these benefits would likely be more pronounced.