Breast cancer survivors may have a slightly lower risk of developing Alzheimer dementia compared with cancer-free individuals, according to the results of a study published by Jeong et al in JAMA Network Open.
“The risk of Alzheimer dementia is a crucial aspect of overall well-being among breast cancer survivors. Concerns about chemobrain and the long-term adverse effects of breast cancer treatment on cognition are common, but our findings suggest that this treatment does not directly lead to Alzheimer dementia,” reported the study authors.
Study Methods and Results
Cancer-related cognitive impairment is a common concern after treatment for patients with breast cancer.
Investigators conducted a retrospective cohort study to determine the risk of Alzheimer dementia in breast cancer survivors compared with cancer-free controls and how breast cancer treatments may impact that risk. Researchers focused on data from 70,701 patients from the Korean National Health Insurance Service who underwent surgery for breast cancer between 2010 and 2016. These patients were matched 1:3 to cancer-free controls. Patients were followed for a median of 7.3 years.
In the breast cancer survivor group, there were 1,229 cases of Alzheimer dementia detected, with an incidence rate of 2.45 per 1,000 person-years vs 2.63 per 1,000 person-years for the control group. Compared with cancer-free controls, survivors showed a slightly lower risk for developing Alzheimer disease (subdistribution hazard ratio [sHR] = 0.92; 95% confidence interval [CI] = 0.86–0.98).
Stratification did not show significant interactions by age group except for those aged 65 or older (sHR = 0.92; 95% CI = 0.85–0.99). Analysis by treatment modality showed that radiation therapy was associated with a significantly lower risk (adjusted HR [aHR] = 0.77; 95% CI = 0.68–0.87). Use of trastuzumab, taxanes, endocrine therapy, aromatase inhibitors, or combined tamoxifen and aromatase inhibitors did not appear to have any association with risk for Alzheimer dementia.
Other risk factors for Alzheimer dementia among breast cancer survivors included smoking (aHR = 2.04; 95% CI = 1.53–2.72), diabetes (aHR = 1.58; 95% CI = 1.36–1.82), and chronic kidney disease (aHR = 3.11; 95% CI = 1.98–4.88). The reduced risk for Alzheimer dementia among breast cancer survivors changed over time, with subdistribution hazard ratios approaching 1.00 as more survival time passed, especially past 5 years. These findings were consistent across all age groups (P = .69).
“Appropriate management of modifiable risk factors for Alzheimer dementia, such as smoking and diabetes, along with standard cancer treatment is a feasible and effective option to lower Alzheimer dementia risk among breast cancer survivors. Understanding the potential protective association of breast cancer on Alzheimer dementia can enhance surveillance strategies for Alzheimer dementia among these survivors,” the authors concluded.
Disclosure: For full disclosures of the study authors, visit jamanetwork.com.
