BREAST cancer survivors may face a lower risk of Alzheimer’s disease than their cancer-free peers, according to a large retrospective cohort study examining long-term cognitive outcomes following treatment.
Researchers analyzed data from more than 70,000 women in South Korea who underwent breast cancer surgery between 2010 and 2016. Compared with matched cancer-free controls, breast cancer survivors showed a modestly reduced risk of developing Alzheimer’s disease (SHR, 0.92; 95% CI, 0.86–0.98) over a median follow-up of 7.3 years. The association was especially pronounced among women aged 65 or older.
The study was designed to address ongoing concerns about cancer-related cognitive impairment, often referred to as “chemo brain,” which is a frequent complaint among patients with breast cancer. However, the data challenge assumptions that breast cancer and its treatments accelerate neurodegeneration. Instead, survivors, particularly those treated with radiation therapy, showed a lower incidence of Alzheimer’s disease. Radiation was associated with a significantly reduced risk (adjusted HR, 0.77; 95% CI, 0.68–0.87), suggesting a possible protective mechanism or selection bias in treatment eligibility.
Still, the lower Alzheimer’s risk was not sustained long-term. Landmark analyses showed that the protective effect observed during the initial years of survivorship diminished after 5 years, raising questions about the duration of any potential benefit. The findings underscore the need for long-term surveillance of cognitive outcomes in this growing population.
Although the exact mechanisms remain unclear, these results provide a nuanced understanding of cognitive risk following breast cancer treatment. They may also help reassure patients concerned about neurocognitive decline during survivorship. Additional research is warranted to explore whether treatment modalities such as radiation contribute directly to neuroprotection or if other factors are at play.
Reference:
Jeong S-M et al. Alzheimer Disease in Breast Cancer Survivors. JAMA Netw Open. 2025;8(6):e2516468.
