Understanding Chemo Brain29 March 2022
Jennifer Kilkus :
"Chemo brain" has a bit of a complicated history. Although the symptoms of feeling foggy, forgetful, and distracted have been well-recognized among cancer survivors for decades, historically, it has been dismissed in the medical community. The thinking behind this reluctance to acknowledge chemo brain was rooted in an understanding that because many chemotherapy drugs don't cross the blood-brain barrier, the symptoms described by patients must be related to the stress of treatment. In recent years, however, there has been a greater understanding of multiple ways that cancer treatment may influence cognition.
What is chemo brain?
Chemo brain, also referred to as chemo fog, or treatment-related cognitive impairment, refers to cognitive changes after cancer treatment: Trouble with attention, concentration, working memory, and executive function. People with a cancer diagnosis describe feeling unusually disorganized, having trouble with multitasking, finding it challenging to remember details or to learn new things, and feeling like their thinking is sluggish. It is common, with most estimates suggesting that up to two-thirds of patients experience this problem1. While most can expect these symptoms to improve 9-12 months after finishing treatment, around 10-20 percent may have these symptoms even years after treatment completion1. "Chemo brain" is also a bit of a misnomer, as radiation, surgery, and hormonal treatments have also all been linked to these cognitive difficulties.
What causes chemo brain?
There is not any one cause for chemo brain. There are likely a number of factors that compound one another that influence these symptoms. There is some evidence that cancer itself can create a pro-inflammatory state that causes inflammatory cytokines to cross the blood-brain barrier, affecting the functioning of neurons.2 Other causes include damage produced by the treatments themselves that occur along with damage directed at cancer cells, including damage to white and gray matter in the brain, microvascular injury, DNA damage, and oxidative stress. Some cancer treatments can also cause treatable conditions such as anemia or nutritional deficiencies that contribute to these symptoms.
The severity of chemo brain is affected by many things, including psychosocial factors (age, education, level of support, anxiety, depression) and medical factors (hormone levels, disease site and stage, and type and length of treatment).
So, while chemo brain is experienced "in your head," there are numerous pathways in your body and environment that can influence your symptoms.
How to manage chemo brain
While there is no quick fix to completely eliminate symptoms of chemo brain, there are effective strategies borrowed from brain injury research that have been demonstrated to help manage cognitive impairment related to cancer treatment.
Your body has the best possible chance to recover from treatment when you're taking good care of it. We know that untreated pain or interrupted sleep can worsen chemo brain, so it's worth talking to your doctor about these issues if they haven't been managed well.
Regular exercise (making sure you're pacing, as I discussed in a previous post) can also help manage symptoms. There is evidence that cardiovascular exercise stimulates the growth of new neurons and improves connections between brain cells.3 It may also alleviate fatigue, which can contribute to chemo brain. A nutritious diet filled with antioxidants and maintaining a healthy weight may also minimize symptoms.
Attending to your emotional well-being is critical for managing chemo brain symptoms. We know that we tend not to think well when we are stressed. In fact, research suggests that the tasks of the prefrontal cortex (the part of our brains that helps with planning, organizing, self-regulation, and keeping up with tasks) are interrupted when our stress level is too high4. When those same processes are already strained due to the effects of treatment, it can become nearly impossible to function well when stress is added on top of it.
Practicing patience and self-compassion is essential, as a flustered mind tends to be a forgetful mind. You may also need to rethink how tasks are distributed in your household. It is easy to get overwhelmed and fall behind if you are overscheduled and inundated by tasks. If you have not been in the habit of prioritizing stress management, now is an excellent time to make that commitment to yourself.
Cognitive and organizational strategies
Research from the cognitive rehabilitation world has shed light on the benefit of organizational and novel learning for chemo brain. Our brains seem to recover faster when we experience new and challenging situations3, while organizational strategies can help compensate for chemo brain symptoms and help everyday tasks feel more manageable.
Chemo brain is challenging and can result in significant frustration and negative self-talk. It's easy to get stuck in a loop of unhelpful thinking, such as "I used to be able to do this, why am I struggling now?," or "I shouldn't have to work so hard at this." Taking a compassionate, accepting approach provides opportunities for shifting from being stuck toward taking steps to adapt to these challenging symptoms.
To find a therapist near you, visit the Psychology Today Therapy Directory.
(Jennifer Kilkus, Ph.D., ABPP, is a board-certified clinical health psychologist. She is an Assistant Professor in the Department of Psychiatry at Yale School of Medicine and a member of the Medical Staff at Yale New Haven Hospital).