Physical Activity, Aerobic Exercise Programs Show Promise in Combating CRCI in Breast Cancer Survivors

Cancer survivor practicing yoga | Image Credit: Halfpoint - stock.adobe.com

A scoping review of research publications found positive outcomes between cancer-related cognitive impairment (CRCI) in breast cancer survivors and moderate to vigorous physical activity, specifically in aerobic training exercise programs.

An electronic database search included literature between January 2000 to December 2021 among observational studies with various designs. The review highlights aerobic exercises and structured programs incorporating moderate to vigorous physical activities (MVPA) in improving cognitive function for breast cancer survivors who haven't opted for, or are still on, hormonal therapy after chemotherapy.

Selected articles included assessments of cognitive function and the quality of life (QoL) of the patients. Factors such as population, intervention, study design, and outcomes were recorded and analyzed after selection. Once the screening process ended, a total of 20 publications were included, 2 of which were follow-up analyses of other studies. Participant ages ranged from 18 to 80 years old with 78% taking active hormonal treatment from between 2 to 10 years after diagnosis. Study designs included cross-sectional (n = 8), longitudinal (n = 1), randomized control trials (n = 7), and randomized crossover trials (n = 2).

The relationship between physical activity and various psychosocial factors were calculated in leisure-time among observational studies. The American College of Sports Medicine defines MVPA as activity of more than 3 metabolic equivalents and when an accelerometer is used, the average daily minutes in MVPA are more than or equal to 1952 counts per minute. Some authors from the articles felt 1 week of recorded physical activity was enough data to observe increased MVPA resulting in depressive symptoms, oncology treatments, and cognitive functions mediating, among many other medical associations. The review identified 30-minute sedentary behavior replacements with 30 minutes of physical activity to examine the relationship of cognitive functions, the influence between self-esteem, and cardiorespiratory fitness.

Of the randomized-control trials with 27% using physical activity-based protocols, 46% had aerobic–training (AT)-based protocols, and 27% began a combined program of AT and resistance training (RT). Training sessions were categorized as either supervised or unsupervised (home-based program) with only 27% reporting both a supervised, home-based training program. Training protocol durations were most used for 1 to 2 years, despite an 8- to 48-week range. Supervised training sessions had frequencies of 2 to 3 days a week with a 40- to 45-minute duration. Only 2 randomized-control trials suggested high-intensity interval training programs with 4 to 7 intervals of 30 seconds each and 2 minutes of recovery in between sets.

Various measurement tools were utilized to assess cognitive function in female breast cancer survivors. The most common of the 16 neuropsychological batteries used was the National Institutes of Health Toolbox Cognition Domain and NeuroTrax Comprehensive Testing Suite. Throughout 80% of the studies, objective measures were conducted to examine cognitive function as a primary variable. Self-reported measures, such as questionnaires, were used to report perceived cognitive abilities and QoL. Objective and subjective measure tools were recommended in only 5 complete studies for assessing cognitive function.

The analysis of collected results found statistically significant impacts on cognition from physical activity-based exercise programs, AT-based programs, and a combination of AT with RT programs. Among intervention groups, processing speeds were the most influenced cognitive domain by both physical activity and AT programs. Moderate effects on working memory and episodic memory were observed as well as processing speed and spatial working memory improvements.

Overall, the review found beneficial effects when exercise was pronounced at higher intensities. A variety of exercise interventions allows skeletal muscles to be an endocrine organ capable of improving the systemic health of the organism.

Study limitations could be prevented by identifying parameters that clarify the relationship between cognitive and emotional impairment with pro-inflammatory levels to reduce bias. Specific CRCI assessment models need to be updated to further understand the connection between brain health and exercise.

Future efforts should focus on the present knowledge gaps on exercise characteristics in relation to muscle-brain through different exercises, intensities, and frequencies based on the treatments the breast cancer survivors experienced.

Reference

Spanoudaki M, Constantinos Giaginis, Dimitra Karafyllaki, et al. Exercise as a promising agent against cancer: evaluating its anti-cancer molecular mechanisms. Cancers. 2023;15(21):5135-5135. doi:10.3390/cancers15215135