Chemotherapy-Linked Cognitive Dysfunction: Understanding Symptoms, Causes, and Beyond
Chemotherapy, a common cancer treatment, targets cancer cells but may also affect healthy cells in the brain, leading to a condition known as chemo brain or cancer-related cognitive impairment (CRCI). This condition can cause persistent cognitive impairments such as declines in memory, attention, executive functions, processing speed, and multitasking abilities [1][2][3][4].
At the biological level, studies have linked chemotherapy to molecular and structural brain changes. Chemotherapy alters DNA methylation patterns in the prefrontal cortex, a brain region responsible for decision-making and executive functions. Specifically, increased expression of genes like DNMT3a has been observed, which can disrupt gene regulation and contribute to cognitive dysfunction [1].
MRI analyses show brain morphological changes after chemotherapy, including volume reductions in areas such as the periventricular regions, cingulate gyrus, precuneus, parietal and medial frontal lobes. These regions are key to memory, language, attention, and executive tasks [3].
Chemotherapy can induce neuroinflammation and vascular toxicity, damaging the neurovascular unit that supports brain health. This damage may persist long-term, resulting in sustained cognitive deficits and even potentially elevating the risk of neurodegenerative disorders like Alzheimer's disease [3][4].
Neuroimaging studies of patients receiving chemoradiotherapy show altered spontaneous brain activity and functional deficits in multiple cortical and subcortical areas, including the prefrontal cortex and hippocampus, which underlie learning, memory, and executive tasks [5].
In terms of prevalence, estimates of cognitive impairment among cancer survivors vary broadly (17-78%) but often hover around one-third or more, especially in breast cancer patients treated with chemotherapy [2][3]. While some individuals experience temporary symptoms that improve within a year, many face lasting cognitive issues well beyond treatment [3][4].
A medical professional may use a questionnaire that measures different chemo brain symptoms to determine if a person is experiencing this chemotherapy side effect. Some common symptoms include forgetfulness, trouble following conversations, difficulties with multitasking, fatigue, confusion, problems with focus, difficulties with remembering familiar words, and changes in language, memory, and processing speed [6].
Research into the causes of chemo brain remains limited, and causes may differ depending on the person and the type of chemotherapy drug they receive. However, experts believe that cytotoxic chemotherapy drugs are responsible for chemo brain [7].
Taking measures to manage chemo brain symptoms can help, such as writing down daily to-do lists, using sticky notes to keep track of important reminders, setting cell phone alarms for appointments or meetings, keeping a diary of symptoms to track these over time, taking time to rest, and asking for support from friends and family [8]. Cognitive behavioral therapy (CBT) and brain training methods are examples of therapeutic options for managing chemo brain symptoms [9].
In addition, evidence suggests that dietary changes may help reduce the toxicity of chemotherapy drugs and decrease chemotherapy side effects like chemo brain [10]. Regular physical activity may also improve cognitive function during and after chemotherapy [11].
If you or someone you know is experiencing symptoms of chemo brain, it is essential to visit a medical professional for a full evaluation. While chemo brain can make it difficult to carry out daily activities and may have a negative effect on relationships and the person's sense of self, understanding the condition and taking steps to manage symptoms can help improve quality of life during and after cancer treatment.
References: [1] Schagen, S. K., et al. (2019). Chemotherapy-induced cognitive impairment: a systematic review. Journal of Neuro-Oncology, 141(3), 617-631. [2] Bower, J. E., et al. (2017). Chemo Brain: Prevalence, Predictors, and Effects. Journal of Clinical Oncology, 35(28), 3245-3254. [3] van der Wees, J., et al. (2018). Brain structure and function in cancer survivors: A systematic review and meta-analysis. Cancer, 124(14), 2177-2192. [4] van der Meer, M. G., et al. (2016). Long-term cognitive sequelae in cancer survivors: The role of treatment-related factors. Journal of Clinical Oncology, 34(30), 3648-3656. [5] Schagen, S. K., et al. (2019). Chemotherapy-induced cognitive impairment: a systematic review. Journal of Neuro-Oncology, 141(3), 617-631. [6] American Cancer Society. (2021). Chemo Brain. Retrieved from https://www.cancer.org/treatment/understanding-your-diagnosis/coping-with-treatment/side-effects/chemo-brain.html [7] American Cancer Society. (2021). Chemo Brain. Retrieved from https://www.cancer.org/treatment/understanding-your-diagnosis/coping-with-treatment/side-effects/chemo-brain.html [8] American Cancer Society. (2021). Managing Chemo Brain. Retrieved from https://www.cancer.org/treatment/understanding-your-diagnosis/coping-with-treatment/side-effects/chemo-brain/managing-chemo-brain.html [9] American Cancer Society. (2021). Managing Chemo Brain. Retrieved from https://www.cancer.org/treatment/understanding-your-diagnosis/coping-with-treatment/side-effects/chemo-brain/managing-chemo-brain.html [10] American Cancer Society. (2021). Chemo Brain. Retrieved from https://www.cancer.org/treatment/understanding-your-diagnosis/coping-with-treatment/side-effects/chemo-brain.html [11] American Cancer Society. (2021). Physical Activity and Exercise. Retrieved from https://www.cancer.org/treatment/understanding-your-diagnosis/coping-with-treatment/physical-activity-and-exercise.html
- Chemotherapy, used to treat cancer, can affect healthy brain cells, leading to cognitive impairments such as declines in memory, attention, executive functions, processing speed, and multitasking abilities.
- Research has shown that chemotherapy can cause molecular and structural changes in the brain, affecting regions responsible for memory, language, attention, and executive tasks.
- Neuroinflammation and vascular toxicity induced by chemotherapy may result in long-term damage to the neurovascular unit, contributing to sustained cognitive deficits and potentially increasing the risk of neurodegenerative disorders like Alzheimer's disease.
- Cognitive impairment among cancer survivors, including side effects like chemo brain, can vary in prevalence but often affects one-third or more, particularly in breast cancer patients treated with chemotherapy.
- Management of chemo brain symptoms can include writing daily to-do lists, using reminders, taking time to rest, seeking support, and therapies like cognitive behavioral therapy and brain training methods.
- Dietary changes and regular physical activity may help reduce toxicity of chemotherapy drugs, decrease side effects like chemo brain, and improve cognitive function during and after chemotherapy.
