The impact of APOE and smoking history on cognitive function in older, long-term breast cancer survivors

A scoping review evaluating physical and cognitive functional outcomes in cancer survivors treated with chemotherapy: charting progress since the 2018 NCI think tank on cancer and aging phenotypes

PURPOSE

The primary goal of this scoping review was to summarize the literature published after the 2018 National Cancer Institute think tank, "Measuring Aging and Identifying Aging Phenotypes in Cancer Survivors," on physical and cognitive functional outcomes among cancer survivors treated with chemotherapy. We focused on the influence of chemotherapy on aging-related outcomes (i.e., physical functional outcomes, cognitive functional outcomes, and frailty), given the known associations between chemotherapy and biologic mechanisms that affect aging-related physiologic processes.

METHODS

A search was conducted across electronic databases, including PubMed, Scopus, and Web of Science, for manuscripts published between August 2018 and July 2023. Eligible studies: 1) included physical function, cognitive function, and/or frailty as outcomes; 2) included cancer survivors (as either the whole sample or a subgroup); 3) reported on physical or cognitive functional outcomes and/or frailty related to chemotherapy treatment (as either the whole sample or a subgroup); and 4) were observational in study design.

RESULTS

The search yielded 989 potentially relevant articles, of which 65 met the eligibility criteria. Of the 65 studies, 49 were longitudinal, and 16 were cross-sectional; 30 studies (46%) focused on breast cancer, 20 studies (31%) focused on the age group 60 + years, and 17 (26%) focused on childhood cancer survivors. With regards to outcomes, 82% of 23 studies reporting on physical function showed reduced physical function, 74% of 39 studies reporting on cognitive functional outcomes found reduced cognitive function, and 80% of 15 studies reporting on frailty found increasing frailty among cancer survivors treated with chemotherapy over time and/or compared to individuals not treated with chemotherapy. Fourteen studies (22%) evaluated biologic mechanisms and their relationship to aging-related outcomes. Inflammation was consistently associated with worsening physical and cognitive functional outcomes and epigenetic age increases. Further, DNA damage was consistently associated with worse aging-related outcomes.

CONCLUSION

Chemotherapy is associated with reduced physical function, reduced cognitive function, and an increase in frailty in cancer survivors; these associations were demonstrated in longitudinal and cross-sectional studies. Inflammation and epigenetic age acceleration are associated with worse physical and cognitive function; prospective observational studies with multiple time points are needed to confirm these findings.

IMPLICATIONS FOR CANCER SURVIVORS

This scoping review highlights the need for interventions to prevent declines in physical and cognitive function in cancer survivors who have received chemotherapy.

Brain white matter microstructural changes in chemotherapy-treated older long-term breast cancer survivors

PURPOSE

To assess white matter microstructural changes in older long-term breast cancer survivors 5-15 years post-chemotherapy treatment.

METHODS

Breast cancer survivors aged 65 years or older who underwent chemotherapy (C+) and who did not undergo chemotherapy (C-) and age- and sex-matched healthy controls (HC) were enrolled at time point 1 (TP1) and followed for 2 years for time point 2 (TP2). All participants underwent brain MRI with diffusion tensor images and neuropsychological (NP) testing with the NIH Toolbox Cognition Battery. Tract-based spatial statistics (TBSS) analysis was performed on the diffusion tensor images to assess white matter microstructural changes with the fractional anisotropy (FA) parameter.

RESULTS

There were significant longitudinal alterations in FA within the C+ group over time. The C+ group showed diminished FA in the body and genu of corpus callosum, anterior corona radiate, and external capsule on both the whole brain and region of interest (ROI) based analyses after p < 0.05 family-wise error (FWE) correction. However, there were no significant group differences between the groups at TP1. Additionally, at TP1, a positive correlation (R = 0.58, p = 0.04) was observed between the FA value of the anterior corona radiata and the crystallized composite score in the C+ group.

CONCLUSIONS

Brain white matter microstructural alterations may be the underlying neural correlates of cognitive changes in older breast cancer survivors who had chemotherapy treatment years ago.

GSK3β rs3107669 polymorphism implicates chemotherapy-associated retrospective memory deficits in breast cancer survivors

Glycogen synthase kinase-3β (GSK-3β) plays an important role in the development of neurodegenerative diseases. However, the underlying effect of GSK-3β polymorphism on chemobrain in cancer survivors is unclear. This study aimed to evaluate the correlation between GSK-3β polymorphism and chemotherapy-associated retrospective memory deficits in breast cancer survivors. The difference in GSK-3β gene expression between breast cancer patients and healthy controls was confirmed using bioinformatics technology. All participants (197 with breast cancer and 40 healthy controls) underwent prospective and retrospective memory tests, and five single-nucleotide polymorphism loci of GSK-3β (rs3107669, rs1154597, rs334543, rs334558 and rs3755557) were genotyped from peripheral blood. Breast cancer survivors had memory impairment after chemotherapy (P<0.0001). The expression difference of the GSK-3β gene was determined through bioinformation analysis, and a genotype frequency difference of GSK-3β rs3107669 was found between the breast cancer and healthy control groups. GSK-3β rs3107669 was a genetic risk in comparison to the healthy controls (OR=0.382; 95% CI=0.186-0.786; P=0.009). Breast cancer with the GSK-3β rs3107669 (C/A+A/A) genotype was a protective factor for chemobrain (Beta=-0.306; 95% CI=-5.556~-2.145; P<0.0001) from multiple linear regression. The C/A+A/A genotype carrier performed better on the retrospective memory test than the C/C genotype (z=-4.302, P<0.0001). Breast cancer patients with chemotherapy who also carried the GSK-3β rs3107669 (C/C) genotype more easily presented cognitive deficits. The GSK-3β rs3107669 polymorphism was a feasible genetic risk factor for chemotherapy-associated retrospective memory impairments in breast cancer survivors.

Cognitive Aging in Older Breast Cancer Survivors

BACKGROUND

Cancer and cancer treatments may affect aging processes, altering the trajectory of cognitive aging, but the extant studies are limited in their intervals of assessment (two-five years). We studied the cognitive performance of a cohort of survivors and controls aged from 60 to 89 years utilizing cross-sectional cognitive performance data as an indicator of potential aging trajectories and contrasted these trends with longitudinal data collected over two years.

METHODS

Female breast cancer survivors who had been diagnosed and treated at age 60 or older and were 5- to 15-year survivors (N = 328) and non-cancer controls (N = 158) were assessed at enrollment and at 8, 16, and 24 months with standard neuropsychological tests and comprehensive geriatric assessment.

RESULTS

A cross-sectional baseline analysis found the expected inverse association of age with cognition in both groups, with survivors performing lower overall than controls in learning and memory (LM). Younger survivors, i.e., those under 75 years of age, exhibited lower performance in both LM and attention, and processing speed and executive function (APE), compared to controls, with no differences being observed between older survivors and controls, which tracked with deficit accumulation trends.

CONCLUSION

Cognitive differences between the survivors and controls for the LM and APE domains were prominent in younger survivors, as was deficit accumulation, suggesting a mediating effect on cognition. Deficit accumulation may represent a modifiable risk factor in cancer survivorship that may be targeted for prevention and intervention.