Carayol, M., Bernard, P., Boiche, J., Riou, F., Mercier, B., Cousson-Gelie, F., . . . Ninot, G. (2013). Psychological effect of exercise in women with breast cancer receiving adjuvant therapy: What is the optimal dose needed? Annals of Oncology, 24, 291–300.

To investigate the effects of an exercise prescription on fatigue, anxiety, depression, and quality of life in patients with breast cancer receiving adjuvant therapy and to explore the relationships between the volume of targeted exercise and the effects observed on these psychological outcomes.

TYPE OF STUDY: Meta-analysis and systematic review

DATABASES USED: MEDLINE, PsycINFO, Pascal, PSYarticles, and Cochrane

KEYWORDS: anxiety, breast cancer, depression, exercise, fatigue, and quality of life

INCLUSION CRITERIA: Participants were adult women diagnosed with breast cancer. Studies had a randomized, controlled experimental design. Intervention programs involving physical activity (yoga-based) were included, whereas relaxation-based interventions were not. An intervention program was scheduled during adjuvant cancer therapy (chemotherapy and/or radiotherapy). At least one psychological outcome among fatigue, anxiety, depression, and quality of life was observed. Pre- and post-intervention data were included to calculate standardized mean differences.

EXCLUSION CRITERIA: Not given

TOTAL REFERENCES RETRIEVED: N = 1,011

EVALUATION METHOD AND COMMENTS ON LITERATURE USED: A quality score based on 10 methodologic criteria specifically chosen for the evaluation of exercise intervention randomized controlled trials and mostly derived from the PEDro scale was calculated for each included study. Targeted exercise volume was estimated using metabolic equivalent for task (MET), where 1 MET accounts for 3.5 ml O₂/kg/min. Corresponding MET values for a given exercise intervention were coded from the Compendium of Physical Activity. Five and 3.8 METs were, respectively, assigned to moderate- and low-intensity aerobic physical activity; strength-training physical activity was coded 3.5 METs; warm-up and cool-down were estimated 2.5 METs if no more detail related to their content was provided; yoga and stretching activities were coded 2.5 METs.                                                        

• N (studies) = 17
• TOTAL PATIENTS INCLUDED IN REVIEW: 748 subjects, 632 controls
• KEY SAMPLE CHARACTERISTICS: The median age of included patients was 50.5 years old. All patients with breast cancer had been diagnosed with nonmetastatic cancer and were undergoing adjuvant therapy (i.e., chemotherapy and/or radiotherapy during exercise intervention).                                                                                                                     

The methodologic quality of the studies had a median score of 7, ranging from 2–9.

PHASE OF CARE: Active anti-tumor treatment

Controlled comparisons of pre- and post-intervention indicated that exercise intervention significantly reduced fatigue, anxiety, and depression, but only borderline significance was reached for anxiety (P = 0.06). Moreover, exercise intervention significantly improved quality of life. Findings showed that higher dose and duration of exercise targets had greater effectiveness. Effect sizes were modest. When low-quality studies were eliminated, effects for fatigue no longer were significant.

Adapted physical activity programs can be expected to decrease fatigue and depressive symptoms and increase quality of life during chemotherapy and/or radiotherapy for patients with early-stage breast cancer. Reduction in anxiety symptoms also was observed, but the evidence still is limited.

A limitation of the study was the estimation of exercise dose. Targeted aerobic exercise intensity frequently was described within a range such as 50%–80% of the maximal heart rate, which did not enable considering it precisely. Except when it was explicitly stated as light or vigorous, intensity was considered moderate for dose calculation. Only targeted exercise doses were estimated instead of achieved exercise doses.

Exercise intervention may improve fatigue, depression, and quality of life in patients with breast cancer receiving adjuvant therapy, with findings suggesting that a prescription of relatively low doses of exercise (less than 12 MET h/week) consisting of about 90–120 minutes of weekly moderate physical exercise seems more efficacious in improving fatigue and quality of life than higher doses.