Treanor, C.J., McMenamin, U.C., O'Neill, R.F., Cardwell, C.R., Clarke, M.J., Cantwell, M., & Donnelly, M. (2016). Non-pharmacological interventions for cognitive impairment due to systemic cancer treatment. Cochrane Database of Systematic Reviews, 8, CD011325.

STUDY PURPOSE: To determine the effectiveness of nonpharmacologic interventions for minimizing chemotherapy-induced cognitive impairment in adult patients with breast cancer.

TYPE OF STUDY: Systematic review

DATABASES USED: MEDLINE, Embase, PubMed, CINAHL, PsycINFO, and CENTRAL (Cochrane Centre Register of Controlled Trials) 

YEARS INCLUDED: (Overall for all databases) 1980 through September 29, 2015

INCLUSION CRITERIA: Randomized controlled trials evaluating the effectiveness of nonpharmacologic interventions on maintaining or improving cognitive function in cancer survivors who completed chemotherapy (including those currently on hormonal therapy)  

EXCLUSION CRITERIA: Studies involving participants with primary or metastatic central nervous system (CNS) disease, nonmelanoma skin cancer, and/or patients in nursing home or residential care settings

TOTAL REFERENCES RETRIEVED: 255 screened (plus 47 additional records), but 40 assessed for study eligibility 

EVALUATION METHOD AND COMMENTS ON LITERATURE USED: Cochrane risk of bias tool was utilized to evaluate study quality.

FINAL NUMBER STUDIES INCLUDED: 5

TOTAL PATIENTS INCLUDED IN REVIEW: 235

SAMPLE RANGE ACROSS STUDIES: 100% female; all patients received chemotherapy and/or hormonal therapy 

KEY SAMPLE CHARACTERISTICS: Breast cancer survivors

PHASE OF CARE: Transition phase after active treatment

Five randomized clinical trials compared an intervention with wait-list controls to improve various cognitive functions (i.e., memory, information processing speed [IPS], executive functioning [EF]). Nonpharmacologic interventions included cognitive behavioral therapy (n = 1), cognitive training (n = 2), meditation through Tibetan sound therapy (n = 1), and aerobic exercise (n = 1).

• Cognitive behavioral therapy significantly improved verbal memory (p < 0.05), but not IPS or patients' perceived cognitive functioning.  
• Two trials evaluated cognitive training. The first study compared cognitive training in IPS or memory to controls and found improved immediate and delayed memory (p < 0.01) in the IPS group as well as better immediate (p = 0.036) and delayed memory (p = 0.013) in the memory group. In addition, both intervention groups found improved subjective cognitive functioning (p < 0.05). The second study used computerized cognitive training and found significant improvements in IPS (p = 0.009) as well as some measures of EF (p = 0.008; p = 0.003).  
• Tibetan sound therapy resulted in no differences for either objective or subjective measures of cognitive function.
• Similarly, no differences were observed between intervention and control groups evaluating aerobic exercise.  

Although cognitive training and cognitive behavioral therapy may be beneficial in improving cognitive functioning, there is insufficient evidence for exercise and meditation. The overall quality of the evidence was determined to be low for all studies included.

Findings from this study revealed that there is insufficient good-quality evidence to determine whether cognitive training, cognitive behavioral interventions, exercise, or meditation may improve cognitive functioning in breast cancer survivors who have received chemotherapy with or without hormonal therapy. However, cognitive training and cognitive behavioral interventions were associated with improvements in objective and subjective measures of cognitive function, so further research including multisite studies with large sample sizes and higher-quality evidence may confirm their effectiveness. Further studies are needed to determine whether exercise and/or meditation might have a role in alleviating cognitive impairment.

Limited number of studies included

Mostly low quality/high risk of bias studies

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