By: Justin Jackson, Phys.org
From: medicalxpress.com
Research led by Samsung Medical Center finds breast cancer survivors exhibit an 8% lower risk of Alzheimer’s dementia (AD) compared with cancer-free individuals, with radiation therapy potentially contributing to the reduced risk.
Breast cancer is the most prevalent cancer affecting women. More than 2.3 million women were diagnosed with breast cancer in 2022, accounting for 11.6% of all cancer cases worldwide. Survival rates now exceed 93% for early-stage disease, transforming breast cancer into a long-term chronic condition for many.
As life expectancy improves, attention has turned toward lasting complications of treatment, particularly effects on cognitive health. Many survivors report memory lapses and difficulty concentrating during and after therapy, a pattern often referred to as cancer-related cognitive impairment or “chemobrain.”
Some studies have reported a lower incidence of dementia in cancer survivors, while others suggest increased risk in older women with breast cancer. Whether breast cancer survivorship alters the risk of AD remains unresolved.
In the study, “Alzheimer Disease in Breast Cancer Survivors,” published in JAMA Network Open, researchers analyzed national health insurance data of AD incidence in breast cancer survivors compared to matched controls without cancer to assess whether breast cancer survivors faced altered risk of AD and to examine associations with treatment.
A retrospective cohort included 70,701 breast cancer survivors who underwent surgery between 2010 and 2016, matched with 180,360 cancer-free individuals. Survivors were observed for an average of 7.3 years, with AD incidence measured through clinical diagnosis confirmed by prescribed dementia medications.
During follow-up, breast cancer survivors had a lower AD incidence rate of 2.45 per 1,000 person-years compared to 2.63 per 1,000 in controls. Notably, survivors aged 65 or older showed a significantly reduced risk.
Intriguingly, the lower AD risk among breast cancer survivors diminished over time, becoming statistically indistinguishable from controls after five years of survivorship—suggesting a window of reduced risk that correlates with treatment timeframes.
Analyzing treatment impacts, radiation therapy emerged as significantly associated with a reduced AD risk among breast cancer survivors (adjusted hazard ratio [AHR], 0.77). Other treatments, including anthracycline chemotherapy and endocrine therapies like tamoxifen and aromatase inhibitors, showed no statistically significant association.
Researchers conclude that breast cancer survivors generally have a modestly reduced short-term risk of AD, particularly after radiation therapy. Given rising survivorship rates, these findings suggest opportunities to refine AD surveillance among cancer survivors and to integrate dementia risk management into survivorship care.
Barbara Jacoby is an award winning blogger that has contributed her writings to multiple online publications that have touched readers worldwide.