Myers, J.S., Erickson, K.I., Sereika, S.M., & Bender, C.M. (2018). Exercise as an intervention to mitigate decreased cognitive function from cancer and cancer treatment: An integrative review. Cancer Nursing, 41, 327–343.

STUDY PURPOSE: To determine the effectiveness of exercise for minimizing cognitive impairment related to cancer and/or cancer-treatment.

TYPE OF STUDY: Systematic integrative review

DATABASES USED: PsycINFO, PubMed, CINAHL

YEARS INCLUDED: (Overall for all databases) though January 2016

INCLUSION CRITERIA: Quantitative studies evaluating effectiveness of exercise for maintaining cognitive functioning in adult patients with cancer with objective and/or subjective assessments 

EXCLUSION CRITERIA: Studies published in a language other than English.

TOTAL REFERENCES RETRIEVED: 232 citations screened, but only 26 met study eligibility criteria.

EVALUATION METHOD AND COMMENTS ON LITERATURE USED: The Grading of Recommendations Assessment, Development and Evaluating tool was used to appraise the quality of evidence for study outcomes.

FINAL NUMBER STUDIES INCLUDED: 26

TOTAL PATIENTS INCLUDED IN REVIEW: 2,145 

SAMPLE RANGE ACROSS STUDIES: 4 to 658 participants.

KEY SAMPLE CHARACTERISTICS: 85% of studies included breast cancer survivors, 77% of all participants received chemotherapy and 31% received radiation therapy.

PHASE OF CARE: Late effects and survivorship

Twenty-six studies evaluated the effectiveness of exercise on improving various cognitive functions (CF) (i.e., memory [M], attention/concentration [AC], executive function [EF], information processing speed [IPS], language [L]) or perceived cognitive function (PCF). Forty-two percent of the studies were randomized controlled trials (n = 11), 42% were quasiexperimental (n = 11), 11.5% were observational (n = 3), and one case study. Interventions included aerobic exercise (n = 4), resistance exercise (n = 3), combination of aerobic and resistance exercise (n = 7), aerobic exercise with another modality (e.g., methylphenidate, psycho-education, behavioral intervention) (n = 4), and mindfulness-based exercise (i.e., yoga, Tai chi, Qigong) (n = 8). Of note, 15% of studies did not have an intervention but, rather, relied on patient self-report regarding exercise.  

Eighty-one percent of studies used subjective measures, but only 35% included objective measures of CF. In addition, there was a great deal of variability between instruments used as well the frequency or timing of evaluation. Eighty-eight percent of studies were longitudinal and assessed patients at baseline until less than three months (26%), three months (52%), or six months (22%). While some studies found significant improvements in PCF and/or various cognitive domains (e.g., IPS, AC, EF, L, M), these results were not consistent across studies.

Findings from this study revealed that there is insufficient good quality evidence to determine whether exercise may improve cognitive functioning in cancer survivors.  Although exercise may be beneficial in improving cognitive functioning, there is insufficient evidence to determine the type of exercise, including duration and frequency, that would be recommended. Additional research, including multi-site studies with large sample sizes and higher quality evidence, are needed to determine the effectiveness that specific types of exercise might have a role in alleviating cognitive impairment.

• Limited search
• Mostly low quality/high risk of bias studies

Study findings do not support recommending exercise for improving cognitive impairment in cancer survivors. However additional research using these interventions are recommended to further determine their effectiveness.