The Effect of Exercise on Cancer-Related Cognitive Impairment and Applications for Physical Therapy: Systematic Review of Randomized Controlled Trials

Abstract

Background Cancer-related cognitive impairment (CRCI), often called “chemo-brain” or “chemo-fog,” is a common side effect among adults with cancer, which can persist well after treatment completion. Accumulating evidence demonstrates exercise can improve cognitive function in healthy older adults and adults with cognitive impairments, suggesting exercise may play a role in managing CRCI. Purpose The purpose was to perform a systematic review of randomized controlled trials (RCTs) to understand the effect of exercise on CRCI. Data Sources Relevant literature was retrieved from CINAHL, Medline (Ovid), and EMBASE. Study Selection Eligible articles were RCTs that prescribed aerobic, resistance, combined aerobic/resistance, or mind-body (eg, yoga or Qigong) exercise during or following cancer treatment and included cognitive function outcome measures. Data Extraction Descriptive information and Cohen d effect sizes were directly extracted or calculated for included trials. Data Synthesis Twenty-nine trials were included in the final analysis. A statistically significant effect of exercise on self-reported cognitive function, both during and postadjuvant treatment, was reported in 12 trials (41%) (Cohen d range: 0.24–1.14), most commonly using the EORTC QLQ-C30. Ten trials (34%) performed neuropsychological testing to evaluate cognitive function; however, only 3 trials in women with breast cancer reported a significant effect of exercise (Cohen d range: 0.41–1.47). Limitations Few RCTs to date have evaluated the effect of exercise on CRCI as a primary outcome. Twenty-six trials (90%) in this review evaluated CRCI as secondary analyses. Conclusions Evidence supporting exercise as a strategy to address CRCI is limited. Future research evaluating CRCI as a primary outcome, including self-reported and objective measures, is needed to confirm the possible role of exercise in preventing and managing cognitive impairments in adults with cancer.

Study protocol of the Aerobic exercise and CogniTIVe functioning in women with breAsT cancEr (ACTIVATE) trial: a two-arm, two-centre randomized controlled trial

“…However, many of these studies have methodological limitations related to study design (i.e., observational, lack of comparison group, small sample size, short duration of follow-up). A particular shortcoming of published studies concerns the approach used to assess cognitive functioning (i.e., reliance on self-report measures, assessment of cognitive functioning as a secondary outcome, using a single item or a subscale of a questionnaire assessing fatigue or quality of life [ 40 ]). Only two published aerobic exercise RCTs have evaluated cognitive functioning as the primary outcome: one in women receiving chemotherapy for breast cancer [ 45 ], the other in women who completed chemotherapy for breast cancer [ 44 ].…”

“…However, the potential of exercise to improve CRCC is unclear. A recent systematic review of 29 published randomized controlled trials (RCTs) found limited evidence for the benefit of exercise compared to usual care on CRCC in adults diagnosed with cancer, including those diagnosed with breast cancer [ 40 ]. Three RCTs in women receiving chemotherapy for breast cancer reported a statistically significant effect of aerobic exercise on CRCC, as measured by performance-based neuropsychological tests (i.e., objective measures [ 41 ] and self-report questionnaires [ 41 – 43 ]).…”

“…In women who had completed chemotherapy for breast cancer, only one small proof-of-concept trial to date reported a statistically significant benefit of aerobic exercise on CRCC, as measured by performance-based neuropsychological tests [ 44 ]. Importantly, in their review, Campbell et al [ 40 ] noted that many of the RCTs identified had evaluated cognitive functioning as a secondary outcome, often using a single item or subscale of a questionnaire assessing fatigue or quality of life. Cognitive functioning was evaluated as the primary outcome in only two RCTs in women diagnosed with breast cancer: one in women receiving chemotherapy [ 45 ] and one in women who had completed chemotherapy [ 44 ].…”

Multidisciplinary standards of care and recent progress in pancreatic ductal adenocarcinoma

“…Various interventions for cancer‐related fatigue have been proposed, ranging from counseling‐based therapy to pharmacotherapy (eg, corticosteroids, methylphenidate), but none have produced a definitive benefit in this patient population. Some evidence suggests that mindfulness techniques and exercise may benefit patients, but available data indicate that benefits are modest and inconsistent 286 …”

Exercise May Affect Metabolism in Cancer-Related Cognitive Impairment

“…These 12 trials used the EORTC QLQ-C30 exam for cognitive functioning. In 10 other trials (34%), neuropsychological testing was used to evaluate cognitive functioning; however, only 3 of these trials in breast cancer reported significant benefits from exercise (Cohen d range: 0.41–1.47) [ 17 ].…”