EXERT-BC: A pilot study of an exercise regimen designed to improve functional mobility, body composition, and strength after the treatment for breast cancer

PURPOSE

Resistance training may offer several unique advantages within breast cancer (BC) survivorship care; however, safety concerns have limited the application of high-intensity compound movements necessary to elicit optimal changes in body composition, strength, and quality of life in this population. The EXERT-BC trial assesses the safety and feasibility of an evidence-based, dose-escalated resistance training regimen among BC survivors, with the goal of improving physical and metabolic function, mobility, muscle mass, and body composition.

METHODS

Participants included women with breast cancer underwent a 3-month thrice weekly exercise regimen involving dose escalation of high-intensity compound exercises. Coprimary outcomes included safety and adherence. Pre- and post-regimen assessment included body composition testing, functional mobility and balance, total load (weight × repetitions × sets) across compound exercises, and patient reported quality of life. Pairwise comparison was performed via the paired t test.

RESULTS

Fourty participants completed a 3-month exercise regimen, with a median age of 57 years (range, 27-74 years) and 73% having stage 0-2 BC. BC therapies concurrent with exercise included anti-estrogen therapy (80%), radiotherapy (30%), and non-hormonal systemic therapy (15%). No adverse events were observed aside from a single case of self-limited knee pain. Session attendance exceeded a prespecified threshold of 75%, and 98% patients reported ongoing compliance to an exercise regimen following regimen completion. Significant reductions in percent body fat (p < 0.001) and increases in percent muscle mass (p = 0.011) were observed. Significant increases in resting metabolic rate (p = 0.023), bilateral grip strength (p < 0.001), functional movement screen (p < 0.001), bilateral Y-Balance testing (p < 0.001), and Godin questionnaire scores (p < 0.001) were observed.

CONCLUSION

A 3-month dose-escalated resistance training regimen comprising high-intensity compound movements appears safe with a high degree of adherence among breast cancer survivors, resulting in demonstrable improvements in body composition, metabolic parameters, strength increases, and patient-reported quality of life.

EXERT-BC: Prospective Study of an Exercise Regimen After Treatment for Breast Cancer

Purpose EXERT-BC is a dose-escalated resistance training regimen created to improve body composition, strength, and balance in women treated for breast cancer (BC). Herein, we report the interim analysis. Women treated for BC underwent this 3-month exercise regimen in an exercise oncology facility with continual monitoring of load and strength. Twenty women completed the IRB-approved protocol, with a mean age of 57 years (range 41-74). Concurrent therapies included anti-estrogen therapy (73%), chemotherapy (14%), and radiotherapy (23%). 27% of women endorsed prior exercise. Subjects missed an average of 1.75 classes (range 0-7), with all meeting adherence over 75%. No injuries or adverse events were reported aside from muscle soreness and 2 days of knee pain. Significant differences in body composition at completion included reduced body fat (38.2% vs. 36.7%, p=0.003), and increased muscle mass (33.1% vs. 37.1%, p<0.001), functional mobility screening (9.82 vs. 11.73, p=0.018), and Y-balance (left: 72.4 vs. 85.3, p=0.001; right: 70.3 vs. 85.2. p<0.001). Significant increases in load were demonstrated: split squat (p<0.001), trap bar deadlift (p=0.035), inclined dumbbell press (p<0.001), and bird dog rows (p<0.001). Dose-escalated resistance training in women with BC is safe and feasible, endorsing significant improvements across body composition, balance, and strength.