Verbal Learning and Memory Function and the Influencing Factors on Breast Cancer Survivors: A Cross-Sectional Study

Is poor sleep quality associated with poor neurocognitive outcome in cancer survivors? A systematic review

PURPOSE

Cancer-related neurocognitive impairment and poor sleep are prevalent in cancer survivors and have a negative impact on their quality of life. This systematic review studies the association between sleep disturbance and neurocognitive functioning, as well as the potential positive effects of sleep interventions on neurocognitive functioning in cancer survivors. In addition, we aimed at determining the potential positive effects of sleep interventions on neurocognitive functioning in this population.

METHODS

Following PRISMA guidelines for reporting systematic reviews and meta-analyses, a comprehensive PubMed, Embase, PsycINFO, and CINAHL search was performed. Inclusion criteria were adult cancer survivors, self-reported or objective measures of neurocognitive functioning and sleep quality, or reports on the association between sleep and neurocognitive functioning.

RESULTS

Of the 4,547 records retrieved, 17 studies were retained for this review. Twelve studies were correlational, and five reported on interventions aimed at improving sleep quality. All studies that included self-reported neurocognitive functioning found that poorer sleep was associated with worse neurocognitive functioning. In four out of eight studies, poorer sleep was associated with objective neurocognitive impairment. Three out of five interventional studies showed neurocognitive functioning improved with improved sleep.

CONCLUSIONS

While poor sleep in cancer survivors is associated with self-reported neurocognitive impairment, the association between poor sleep and objective neurocognitive impairment is less evident.

IMPLICATIONS FOR CANCER SURVIVORS

It is important that care providers are aware of the association between sleep and neurocognitive functioning and that improving sleep quality can be a way to decrease neurocognitive impairment in cancer survivors.

Global prevalence of sleep disturbances among breast cancer survivors: A systematic review with meta-analysis

Breast cancer is a common cancer in which patients are highly susceptible to different sleep disturbances. However, current evidence lacked consistency in methodologies in investigating the prevalence of sleep disturbances among breast cancer survivors. The review aims to (1) investigate the global prevalence of sleep disturbances among breast cancer survivors; and (2) investigate the factors influencing the prevalence estimates. A comprehensive search was conducted in 8 databases using a 3-step approach, up to January 2022. The Newcastle-Ottawa Scale and Cochrane risk of bias tool were used to evaluate the quality of individual studies. Meta-analysis, meta-regression, and subgroup analysis were performed using R software. Certainty of evidence was assessed using Grading of Recommendations, Assessment, Development, and Evaluations criteria. A total of 51 studies were selected involving 28,036 breast cancer survivors across 17 countries. The global prevalence of poor sleep quality was 62%, different severities of insomnia were 3%-32%, and excessive daytime sleepiness was 24%. Subgroup analyses showed that a significantly higher prevalence of poor sleep quality was found in breast cancer survivors during treatment compared with pre- or post-treatment. No significant covariates were found in a series of meta-regression analyses. The majority (73.5%) of individual studies were high quality but the certainty of the evidence was low or very low according to Grading of Recommendations, Assessment, Development, and Evaluations criteria. More than half of breast cancer survivors have sleep disturbances, so developing a strategic intervention is warranted. Given the low or very low certainty of the evidence, a robust design for large-scale research is crucial in the future.

Prevalence of cognitive impairment following chemotherapy treatment for breast cancer: a systematic review and meta-analysis

Breast cancer survival rates have markedly improved. Consequently, survivorship issues have received increased attention. One common sequel of treatment is chemotherapy-induced cognitive impairment (CICI). CICI causes a range of impairments that can have a significant negative impact on quality of life. Knowledge of the prevalence of this condition is required to inform survivorship plans, and ensure adequate resource allocation and support is available for sufferers, hence a systematic review of prevalence data was performed. Medline, Scopus, CINAHL and PSYCHInfo were searched for eligible studies which included prevalence data on CICI, as ascertained though the use of self-report, or neuropsychological tests. Methodological quality of included studies was assessed. Findings were synthesised narratively, with meta-analyses being used to calculate pooled prevalence when impairment was assessed by neuropsychological tests. The review included 52 studies. Time-points considered ranged from the chemotherapy treatment period to greater than 10 years after treatment cessation. Summary prevalence figures (across time-points) using self-report, short cognitive screening tools and neuropsychological test batteries were 44%, 16% and 21-34% respectively (very low GRADE evidence). Synthesised findings demonstrate that 1 in 3 breast cancer survivors may have clinically significant cognitive impairment. Prevalence is higher when self-report based on patient experience is considered. This review highlights a number of study design issues that may have contributed to the low certainty rating of the evidence. Future studies should take a more consistent approach to the criteria used to assess impairment. Larger studies are urgently needed.

Cognitive effects of chemotherapy: An integrative review

PURPOSE

An estimated 18.1 million new cancer cases (excluding nonmelanoma skin cancers) were diagnosed worldwide in 2020. Despite a rising incidence of cancers worldwide, in developed countries with strong healthcare systems, survival rates are improving as a result of early detection, improved treatments and survivorship care (World Health Organisation (WHO), 2021). Whilst living longer, cancer survivors are often living with side effects of treatment, including chemotherapy related cognitive impairment, often termed "chemobrain".

METHOD

An integrative review of contemporary literature answering the research question how does chemotherapy affect cognitive function? was undertaken utilising three computerised databases CINAHL, Medline and PUBMED, between 2015 and 2021. Data was thematically analysed to identify themes within published literature.

RESULTS

Thematic analysis identified four broad themes within the literature regarding chemotherapy induced cognitive impairment. Identified themes included; cognition as part of a complex scenario, proof of existence and searching for the cause, learning to play the game and timing of cognitive impairment.

CONCLUSIONS

Aggressive treatment with chemotherapy in the adjuvant setting has drastically improved the survival of cancer patients. Subsequent to aggressive treatments, side effects such as cognitive impairment have presented, which may persist in the long term. Despite the exact aetiology of chemotherapy induced cognitive impairment being largely unknown, the consequences of the condition are impacting cancer survivors and their quality of life.