A cohort study from Samsung Medical Center in South Korea investigated Alzheimer’s prevalence in breast cancer survivors. The researchers compared Alzheimer’s prevalence to several cancer treatment approaches, as well as a group of healthy women. According to the findings, breast cancer survivors who underwent radiation therapy had an 8% lower risk of developing Alzheimer’s.
The American Cancer Society estimates that women have a one in eight risk of getting breast cancer at some point, making it one of the most prevalent malignancies among women [1].
Alzheimer’s disease is another public health concern at the same time, affecting approximately 7 million people in the US alone [2].
Since long-term cognitive adverse effects are a significant concern associated with cancer treatments, a cohort study led by researchers from Samsung Medical Center in South Korea investigated whether breast cancer treatments affect the risk of Alzheimer’s.
The journal JAMA Network Open published the study [3].
Breast Cancer Treatments
The 5-year relative survival rate for breast cancer is 91% [4]. Whether the cancer is localized (it is only in the place where it started) or has metastasized (spread beyond the breast) determines the course of treatment.
Metastatic breast cancer is harder to treat and necessitates more intensive therapy than localized breast cancer.
Some of the cancer treatment methods are:
- surgery such as a lumpectomy or mastectomy
- radiation therapy (also known as radiotherapy)
- hormone (endocrine) therapy
- targeted therapy
- Immunotherapy.
Radiation therapy is a common therapeutic option for breast cancer, even in its early stages. About 40% of women with breast cancer have chemotherapy, and 70% undergo radiation therapy [5].
Serious adverse effects are possible with these cancer treatments; radiation therapy may result in cognitive impairment, exhaustion, and hair loss. Fatigue, neuropathy, and cognitive abnormalities (chemo brain) are a few of the side effects of chemotherapy.
What is Chemo Brain?
Globally, breast cancer is the most prevalent cancer among women. However, survival rates have significantly increased because of the improved treatments and early screening. This has led to a higher emphasis on survivorship.
Survivors of breast cancer often experience cognitive problems after therapy. It is referred to as “chemo brain.”
Previous research has looked into the relationship between Alzheimer’s disease and cancer treatment.
According to a recent study, older persons with cancer were much less likely than the general population to develop Alzheimer’s disease and related dementia [6].
Other studies, however, have demonstrated the contrary [7,8].
The Recent Research: What’s the link between Radiotherapy and Alzheimer’s?
Now, the recent study has demonstrated that breast cancer survivors who underwent radiation therapy had a lower risk of developing Alzheimer’s. One of the study’s authors, Su-Min Jeong, MD, assistant professor in the Department of Medicine at Seoul National University College of Medicine, stated that radiation treatment may have some neuroprotective effects on the survivors’ brains. She went on to say that they looked through some of the literature and discovered that Alzheimer’s can be treated with low-dose radiation therapy [9].
The researchers in the new study looked at the risk of Alzheimer’s disease among breast cancer survivors using data from the Korean National Health Insurance Service. They comprised a control group of approximately 180,000 women and a group of about 70,000 breast cancer survivors.
The patients received cancer surgery and treatment from 2010 to 2016; the researchers analyzed an average of seven years of follow-up data for breast cancer survivors.
Radiation therapy was the most prevalent cancer treatment (received by 71.7% of the group). Nearly half of the women had hormone treatments, and over half received chemotherapy medications.
Radiotherapy associated with lower short-term Alzheimer’s risk
In the breast cancer group, 1,229 women were diagnosed with Alzheimer’s throughout the follow-up period.
Women who had received therapy for breast cancer had an 8% reduced Alzheimer’s risk compared to the control group.
The women who received radiation therapy showed the most significant risk reduction, leading the researchers to speculate that radiation may have contributed to the decreased risk of Alzheimer’s.
However, the researchers found that this protective effect diminished over time. Based on these results, the authors postulated that the risk of Alzheimer’s dementia would decrease soon after cancer therapy, but it might level out as survival time increases.
Despite the apparent preventive advantage of radiation therapy, the study found that other therapies had no discernible effect on the risk of Alzheimer’s.
Limitations and Future Prospects
Researchers noted that the study had limitations, including missing information on cancer stage as well as radiation fraction and dose.
Moreover, the study is observational, has a Korean base, and lacks information about family history or tumor biology.
The maximum follow-up duration in this study was only 11 years, which may have been insufficient to completely comprehend the long-term association between breast cancer therapies and Alzheimer’s risk, the authors noted, underscoring the need for further research.
Longer-term studies and research on different forms of cancer are also worthy of attention.
According to Jeong, one of the primary factors affecting cancer survivors’ quality of life following treatment is their likelihood of developing dementia. A crucial area for future research is examining health problems that impact cancer survivors’ quality of life.
Alzheimer’s Research Association is a non-profit organization dedicated to helping caregivers of Alzheimer’s disease and dementia. We provide the latest information and news about the illness and helpful tips to help caregivers cope with their daily caregiving challenges. We realize the most important thing that a caregiver needs is financial assistance. Therefore, we provide grants to caregivers to ease their financial burden. Caregivers can apply for grants here: Alzheimer’s Grant Application.
You can also help caregivers in their endeavor by donating as much as possible: Donation To Alzheimer’s Research Associations.
References
- Breast Cancer Facts and Figures 2024-2025. American Cancer Society. Atlanta: American Cancer Society. https://www.cancer.org/content/dam/cancer-org/research/cancer-facts-and-statistics/breast-cancer-facts-and-figures/2024/breast-cancer-facts-and-figures-2024.pdf. Accessed: 11th August, 2025.
- Alzheimer’s Disease Facts and Figure. Alzheimer’s Association. https://www.alz.org/alzheimers-dementia/facts-figures. Accessed: 11th August, 2025.
- Jeong, S.M., Jung, W., Cho, H., Choi, H.L., Jeon, K.H., Nam, K.W., Lee, Y.G., Kim, B., Han, K. and Shin, D.W., 2025. Alzheimer Disease in Breast Cancer Survivors. JAMA Network Open, 8(6), pp.e2516468-e2516468.
- Survival Rates for Breast Cancer. AmericanCancer Society. https://www.cancer.org/cancer/types/breast-cancer/understanding-a-breast-cancer-diagnosis/breast-cancer-survival-rates.html. Accessed: 11th August, 2025.
- Maliko, N., Stam, M.R., Boersma, L.J., Vrancken Peeters, M.J.T., Wouters, M.W., KleinJan, E., Mulder, M., Essers, M., Hurkmans, C.W. and Bijker, N., 2022. Transparency in quality of radiotherapy for breast cancer in the Netherlands: a national registration of radiotherapy-parameters. Radiation Oncology, 17(1), p.73.
- Bassil, D.T., Zheng, B., Su, B., Kafetsouli, D., Udeh-Momoh, C., Tzoulaki, I., Ahmadi-Abhari, S., Muller, D.C. and Middleton, L.T., 2024. Lower incidence of dementia following cancer diagnoses: Evidence from a large cohort and Mendelian randomization study. The Journal of Prevention of Alzheimer’s Disease, 11(5), pp.1397-1405.
- Wennberg, A., Ding, M., Feychting, M. and Modig, K., 2023. Risk of all-cause dementia, Alzheimer disease, and vascular dementia in breast cancer survivors: a longitudinal register-based study. Neurology: Clinical Practice, 13(4), p.e200173.
- Chu, C.S., Cheng, S.L., Bai, Y.M., Su, T.P., Tsai, S.J., Chen, T.J., Yang, F.C., Chen, M.H. and Liang, C.S., 2025. Risk of dementia in different types of cancer survivors: a nationwide cohort study. The American Journal of Geriatric Psychiatry, 33(2), pp.156-166.
- Risk for Alzheimer’s disease lower among breast cancer survivors than general population. Healio. https://www.healio.com/news/hematology-oncology/20250724/risk-for-alzheimers-disease-lower-among-breast-cancer-survivors-than-general-population. Published Online: 24th July, 2025. Accessed: 11th August, 2025.
- Watts, E. Radiotherapy for breast cancer linked to lower Alzheimer’s risk. Medical News Today. https://www.medicalnewstoday.com/articles/radiotherapy-for-breast-cancer-linked-to-lower-alzheimers-risk. Published Online: 5th July, 2025. Accessed: 11th August, 2025.
- Carragher, P. Breast Cancer Survivors May Face Lower Risk of Alzheimer’s, Study Finds. Moffitt Cancer Center. https://www.moffitt.org/endeavor/archive/breast-cancer-survivors-may-face-lower-risk-of-alzheimers-study-finds/. Published Online: 15th July, 2025. Accessed: 11th August, 2025.
