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. The purpose was to perform a systematic review of randomized controlled trials (RCTs) to understand the effect of exercise on CRCI. Relevant literature was retrieved from CINAHL, Medline (Ovid), and EMBASE. 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. Descriptive information and Cohen d effect sizes were directly extracted or calculated for included trials. 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). 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. 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.

Objectives To update our previous evaluation of the exercise interventions used in randomised controlled trials of breast cancer survivors in relation to (1) the application of the principles of exercise training in the exercise prescription; (2) the reporting of the components of the exercise prescription; and (3) the reporting of adherence of participants to the prescribed interventions. Design Systematic review. Data sources The OVID Medline, Embase, CINAHL and SPORTDiscus electronic databases were searched from January 2010 to January 2017. Eligibility criteria Randomised controlled trials of at least 4 weeks of aerobic and/or resistance exercise in women diagnosed with breast cancer, reporting on physical fitness or body composition outcomes. Results Specificity was appropriately applied by 84%, progression by 29%, overload by 38% and initial values by 67% of newly identified studies. Reversibility was reported by 3% anddiminishing returns by 22% of newly identified studies. No studies reported all components of the exercise prescription in the methods, or adherence to the prescribed intervention in the results. Reporting of reversibility has increased from 2010, but no other improvements in reporting were noted from the previous review. Summary/Conclusion No studies of exercise in women with breast cancer attended to all principles of exercise training, or reported all components of the exercise prescription in the methods, or adherence to the prescription in the results. Full reporting of the exercise prescribed and completed is essential for study replication in research and translating research findings into the community, and should be prioritised in future trials.

To prospectively assess adherence to oncologist-referred, exercise programming consistent with current recommendations for cancer survivors among women with early breast cancer across the trajectory of adjuvant treatment. Sixty-eight women participated in supervised, hour-long, moderate-intensity, aerobic and resistance exercise 3x/week during adjuvant chemotherapy ± radiation, with a step-down in frequency for 20 additional weeks. Adherence to exercise frequency (i.e. attendance), intensity, and time/duration, and barriers to adherence were tracked and compared during chemotherapy versus radiation, and during treatment (chemotherapy plus radiation, if received) versus after treatment. Attendance decreased with cumulative chemotherapy dose (cycles 1-2 vs. cycles 3-8, cycle 3 vs. cycles 7-8, all P ≤ 0.05), and was lower during chemotherapy than radiation (64 ± 25 vs. 71 ± 32%, P = 0.02), and after treatment than during treatment (P < 0.01). Adherence to exercise intensity trended toward being higher during chemotherapy than radiation (69 ± 23 vs. 51 ± 38%, P = 0.06), and was higher during than after treatment (P = 0.01). Adherence to duration did not differ with treatment. Overall adherence to the resistance prescription was poor, but was higher during chemotherapy than radiation (57 ± 23 vs. 34 ± 39%, P < 0.01), and was not different during than after treatment. The most common barriers to attendance during treatment were cancer-related (e.g. symptoms, appointments), and after treatment were life-related (e.g. vacation, work). Adherence to supervised exercise delivered in a real-world clinical setting varies among breast cancer patients and across the treatment trajectory. Behavioral strategies and individualization in exercise prescriptions to improve adherence are especially important for later chemotherapy cycles, after treatment, and for resistance exercise.