Predictors of supervised exercise adherence during breast cancer chemotherapy.

PURPOSE Exercise adherence is difficult during cancer treatments, but few studies have examined the predictors of such exercise. Here, we report the predictors of adherence to supervised exercise training during breast cancer chemotherapy. METHODS Breast cancer patients (N = 242) initiating adjuvant chemotherapy in Edmonton, Ottawa, and Vancouver were randomly assigned to usual care (n = 82), supervised resistance exercise (n = 82), or supervised aerobic exercise (n = 78) for the duration of their chemotherapy. Baseline data on standard demographic, medical, behavioral, fitness, and psychosocial variables as well as motivational variables from the Theory of Planned Behavior were collected. Adherence was assessed by objective attendance records. RESULTS Adherence to supervised exercise was 70.2%. Univariate analyses indicated significant or borderline significant associations between exercise adherence and location/center (r = 0.30; P < 0.001), V[spacing dot above]O2peak (r = 0.21; P = 0.008), muscular strength (r = 0.21; P = 0.008), percent body fat (r = -0.21; P = 0.012), disease stage (r = 0.17; P = 0.031), education (r = 0.15; P = 0.053), depression (r = -0.14; P = 0.073), and smoking (r = -0.14; P = 0.081). In multivariate analysis, location/center (beta = 0.28; P = 0.001), V[spacing dot above]O2peak ([beta] = 0.19; P = 0.016), disease stage (beta = 0.18; P = 0.015), and depression (beta = -0.16; P = 0.033) remained significant and explained 21% of the variance in exercise adherence. Participants in Vancouver, with higher aerobic fitness, more advanced disease stage, and lower depression, achieved better adherence. CONCLUSION Adherence to supervised exercise training was predicted by unique aspects of the location/center, disease stage, aerobic fitness, and depression but not motivational variables. Location/center in our trial may have been a proxy for the amount of one-on-one attention received during supervised exercise. These findings may have implications for improving adherence during breast cancer chemotherapy.

[1]  C. Friedenreich,et al.  Six-Month Follow-up of Patient-Rated Outcomes in a Randomized Controlled Trial of Exercise Training during Breast Cancer Chemotherapy , 2007, Cancer Epidemiology Biomarkers & Prevention.

[2]  C. Friedenreich,et al.  Effects of aerobic and resistance exercise in breast cancer patients receiving adjuvant chemotherapy: a multicenter randomized controlled trial. , 2007, Journal of clinical oncology : official journal of the American Society of Clinical Oncology.

[3]  A. Bauman,et al.  Physical activity and public health: updated recommendation for adults from the American College of Sports Medicine and the American Heart Association. , 2007, Circulation.

[4]  N. Mutrie,et al.  Benefits of supervised group exercise programme for women being treated for early stage breast cancer: pragmatic randomised controlled trial , 2007, BMJ : British Medical Journal.

[5]  K. Courneya,et al.  Effects of exercise on breast cancer patients and survivors: a systematic review and meta-analysis , 2006, Canadian Medical Association Journal.

[6]  K. Courneya,et al.  Predictors of adherence and contamination in a randomized trial of exercise in colorectal cancer survivors , 2004 .

[7]  K. Courneya,et al.  Three independent factors predicted adherence in a randomized controlled trial of resistance exercise training among prostate cancer survivors. , 2004, Journal of clinical epidemiology.

[8]  D. Cella,et al.  Combining anchor and distribution-based methods to derive minimal clinically important differences on the Functional Assessment of Cancer Therapy (FACT) anemia and fatigue scales. , 2002, Journal of pain and symptom management.

[9]  A. Bauman,et al.  Correlates of adults' participation in physical activity: review and update. , 2002, Medicine and science in sports and exercise.

[10]  Ryan E. Rhodes,et al.  Correlates of adherence and contamination in a randomized controlled trial of exercise in cancer survivors: An application of the theory of planned behavior and the five factor model of personality , 2002, Annals of behavioral medicine : a publication of the Society of Behavioral Medicine.

[11]  S. Biddle,et al.  A Meta-Analytic Review of the Theories of Reasoned Action and Planned Behavior in Physical Activity: Predictive Validity and the Contribution of Additional Variables , 2002 .

[12]  Adrienne R. Sinden,et al.  Who Will Stay and Who Will Go? A Review of Older Adults’ Adherence to Randomized Controlled Trials of Exercise , 2001 .

[13]  P. Williams,et al.  Physical activity and public health. , 1995, JAMA.

[14]  I. Ajzen.  The theory of planned behavior , 1991 .

[15]  C. Rock,et al.  Correlates of physical activity level in breast cancer survivors participating in the Women’s Healthy Eating and Living (WHEL) Study , 2006, Breast Cancer Research and Treatment.

[16]  H. Hausenblas,et al.  The Theories of Reasoned Action and Planned Behavior Applied to Exercise:A Meta-analytic Update , 2005 .

[17]  I. Ajzen.  Nature and operation of attitudes. , 2001, Annual review of psychology.