Chemobrain: 1 in 3 breast cancer survivors suffer from cognitive impairment

Woman in gymnasium with allied health professional

Activities such as exercise and meditation practice can help alleviate stress associated with the side effects of chemotherapy treatment.

Are you a breast cancer survivor and do you forget things?

An analysis of breast cancer research by University of Adelaide and University of Manchester scientists has found that 1 in 3 people who survive breast cancer have clinically significant cognitive impairment.

Also known as ‘chemobrain’, cognitive impairment is a common side effect of cancer treatments which can affect patients’ ability to return to work, perform everyday tasks and sustain relationships. For example, patients often report being unable to recall which day of the week it is, or forget a familiar route while driving.

University of Adelaide behavioural neuroscientist Alexandra Whittaker who led the international study, said chemobrain had been previously studied mostly in patients with breast cancer.

“While it is common for women to report some level of cognitive decline, estimates of the rate at which this happens, and the duration of impact, have been highly varied in previous research,” Dr Whittaker said.

In our research, we performed a type of study called a meta-analysis. This brings together all the previous research on a topic and uses mathematical methods to come up with a summary estimate based on all the data,” Dr Whittaker said.

“Our research findings suggest that clinically significant cognitive impairment occurs in 1 in 3 survivors of breast cancer.

“Another striking finding was that rates of cognitive decline were still around 20% at three years after treatment had stopped. In around 10% of patients, decline was still present 10 years after the end of treatment.”

Over recent years with the advent of new chemotherapy treatments, cancer survivorship has significantly increased. But, with more patients living beyond their diagnosis issues of quality of life have become more pressing.

Cancer treatments typically cause a wide range of side-effects. Many of these, such as gut disturbances are short term. However, chemotherapy can cause changes to the nervous system which may be longer lasting.

Dr Whittaker said the research uncovered reasons for the previous variability reported in chemobrain occurrences.

“Firstly, few patients are offered formal cognitive testing to diagnose chemobrain, yet they recognise a decline in function and self-report this,” she said.

“Rates of chemobrain diagnosed by patient self-report were generally higher. This could be due to the impact of fatigue and stress because of cancer treatment on cognitive function, which tends to have a greater influence when self-report methods are used.

“A second critical reason is that formal testing of cognition compares levels against the norm expected of an average person. However, a patient may be functioning well above the norm for the population pre-cancer, experience a decline, but still fall within normal levels.

“So, they may experience significant loss of cognitive function, but the test says they are OK. These patients may then miss out on the opportunity to receive information and support on managing the condition.”

While there are currently no drug treatments for managing chemobrain, other research has shown that adoption of a range of strategies can improve symptoms.

Dr Whittaker said that activities such as exercise and meditation practice are likely to help through alleviating stress.

“Using aids to organise tasks also assists in completing day-to-day activities. The creation of lists, use of reminder tools and maintaining a distraction-free environment can all be helpful.”

The research published in Scientific Reports was undertaken by Dr Whittaker – a Senior Lecturer in the University of Adelaide’s School of Animal and Veterinary Sciences; Dr Rebecca George from the University of Adelaide’s School of Biomedicine; and Dr Lucy O’Malley from the Manchester Academic Health Sciences Centre at the University of Manchester.

About the author

Alexandra Whittaker

Alexandra Whittaker is a veterinary scientist, lawyer, and behavioural neuroscientist who researches the impact of neuroimmune alterations on emotion and cognitive processing.

She leads an interdisciplinary team of University of Adelaide researchers skilled in animal and veterinary sciences, social sciences, regulation and governance, and evidence-based practice. The team also collaborates with scientists within the health, medical and biological science fields.

Alex also leads the Evidence Synthesis Initiative for Animal and Veterinary Sciences (ESIAVS) initiative, a team of researchers who provide up-to date, relevant, high-quality evidence to support decision-making in the animal industries and veterinary practice.

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Tagged in Research, School of Biological Sciences, School of Animal and Veterinary Sciences, Biomedical Science, Veterinary Medicine