'Chemo brain'

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If you or someone you love has gone through the trial of chemotherapy for treatment of cancer, you have no doubt heard about many unpleasant side effects.

Nausea, tenderness, hair loss, weakness and fatigue are just a very few common side effects during treatment. The list of difficult symptoms is long and daunting. Once the final round of treatment is complete, the body slowly begins to recover and regain some strength. But even after the bulk of side effects have subsided, many survivors will talk about a phenomenon called ‘chemo brain’.

For some reason, after chemotherapy, between 20 and 30 percent of people experience some cognitive impairment. Symptoms can include: confusion, difficulty concentrating, fatigue, mental fogginess, fatigue, poor attention, difficulty finding the right word, poor memory and others. Symptoms typically last for a few years after treatment.

Until recently, there was some debate about the existence of this ‘chemo brain’ phenomenon but studies have indeed shown it to be a real and measurable side effect of chemotherapy in some people.

Although many people experience temporary cognitive impairment due to the stress, fatigue and depression that goes along with cancer diagnosis and treatment, the longer term symptoms of ‘chemo brain’ are another matter. Interestingly, they seem to mostly affect people experiencing breast, ovarian, prostate or other cancers of the reproductive system.

Studies have now shed some light into what may be causing these symptoms. Researchers at West Virginia University conducted brain imaging studies using PET/CT scans to show a physiological basis for post-chemotherapy cognitive impairment.

In the study, brain metabolism was compared before and after chemotherapy in 128 breast cancer patients. Results showed two brain regions with decreased metabolism after chemotherapy. The affected areas – the superior medial frontal gyrus and the temporal operculum – are known to be involved in prioritizing, problem solving, organizing and long-term memory. Not surprisingly, these are the areas often affected in ‘chemo brain’.

Since we now have more people surviving cancer and also receiving more aggressive chemotherapy treatment, this condition has become increasingly clinically important. Cognitive function can be measured. Ideally a person could have their cognitive functioning assessed before chemotherapy and then again after. This would allow comparison of before and after functioning for a specific individual. Alternatively, if one measures only when symptoms are noticed, one can compare functioning of that individual to an age and education matched control group. This is not as precise, but better than nothing. Cognitive impairment is very hard to assess from interview alone, except in very severe cases.

More research is needed to fully understand the condition, the prognosis for those who experience it and to determine if there are ways it can be prevented, treated or minimized while still effectively targeting the cancer.

This article is written by or on behalf of an outsourced columnist and does not necessarily reflect the views of Castanet.