Neurocognitive impact in adjuvant chemotherapy for breast cancer

Share :
Published: 17 Dec 2012
Views: 7046
Prof Bernadine Cimprich - University of Michigan School of Nursing, Ann Arbor, USA

Possible changes in cognitive function over the course of chemotherapy, directly relating to fatigue.


Prof Cimprich explains that in this prospective study, possible alterations in neurocognitive responses, namely, working memory, occur from pre- to post- adjuvant treatment during functional magnetic resonance imaging and further investigated whether early fatigue might be linked to cognitive alterations over time. 

SABCS 2012

Neurocognitive impact in adjuvant chemotherapy for breast cancer

Professor Bernadine Cimprich – University of Michigan School of Nursing, Ann Arbor, USA

I presented findings from our study that explored and examined the possible changes that women might experience in their cognitive functioning over the course of chemotherapy and whether or not fatigue might be a contributing factor to cognitive problems that women may experience over time. What we found using functional magnetic resonance imaging was that women, whether getting chemotherapy or radiation therapy before they had any adjuvant treatment, actually had cognitive problems, had some alteration in their neural function, were more worried and were more fatigued before they actually had any adjuvant treatment. And of interest was that… and this was in comparison with our controls, which were women who were age matched without diagnosis of cancer who had had a negative screening mammogram. What we found, that was somewhat surprising, was that the chemotherapy group of women, before any adjuvant chemotherapy, were more worried and more fatigued than were the other groups. We also found that the lower level of activation before any treatment predicted increases in the level of fatigue over time. Actually our chemotherapy group showed the lowest level of activation in an area of the brain in the prefrontal cortex called the left inferior frontal gyrus. This is an important region of interest for us because the working memory task that women did in the scanner in terms of neural activation, this region is very important to support effective working memory. Typically as a task increases, the difficulty increases, the level of activation should be observed that increases as well and we saw that in our healthy controls. Our patient groups, however, had a different pattern of activation over time than did the healthy controls.

Is the chemotherapy the reason for this fatigue?

We’re saying, first of all, that we do not know what the independent effects of chemotherapy are. There are certainly studies that show that women do have cognitive problems involved with chemotherapy and following chemotherapy. What we are saying is that there are other factors, such as fatigue, that can either compound problems that women might have in response to chemotherapy or that could actually cause problems that wouldn’t otherwise exist. So we’re saying that there are probably multiple reasons why women experience cognitive problems over the course of adjuvant treatment, whether it’s chemotherapy or radiation therapy, and that fatigue and pre-treatment worry and reductions in their ability to respond neurally in brain function to a working memory task contribute over time to the severity of the problems.

What about the interventions that could reduce these problems?

Given that now there is a possibility that there are other sources or reasons why women might experience these cognitive difficulties that are actually observable before any adjuvant treatment, it suggests that there are multiple possible interventions which did not actually… or were not considered before. So, first of all, we know that there are some tested interventions to reduce fatigue, particularly the increase in activity or exercise depending on the capacity of a woman and her ability to do exercise, but it has been shown to reduce the level of fatigue over the course of treatment. That’s a little counter-intuitive but it does improve physical function. Also, if you improve fatigue in that instance you will also have an effect on cognitive function because then functioning will not be as effortful. In terms of helping women to keep their worry manageable, which worry, I think, is unavoidable, the problem is when it gets out of control, we did see that worry interfered with the person’s ability to do the working memory task before any treatment, that was in the scanner task. So there are interventions that might be recommended and they would include interventions such as relaxation techniques, mindfulness, which is similar to relaxation, to help women to have a more manageable time with worry. There are also interventions that involve exposure to the natural environment, there’s a nice body of work now and this is a very modest intervention that almost anyone can do and that is to spend at least regular periods of time every week in a natural environment or in nature. It could be as simple as walking in a natural environment or sitting or bird watching or going to a botanical garden, but we have seen that exposure to nature has a spontaneous relaxation effect on the brain and so it helps those parts of the brain that are fatigued to become restored and people feel a sense of stronger mental capacity and attention and working memory. So these are some interventions, there are more, and this is a great opportunity for nurses and physicians and researchers, other clinicians, to consider in speaking with women kinds of interventions that they might prefer and that might be most appropriate for them. This should be done, I should say, I think, before the start of any adjuvant treatment so that it’s a kind of pre-emptive strike. Even if you’re not having difficulties with your cognitive function before the start of chemotherapy this is a way to try to maintain your function over the course, or at least to improve it, over the course of treatment.

What about the effect of abandonment?

I think this has been an area of work that has received quite a bit of attention in the sense that one of the researchers in an article presented on this said that women felt like they were cast adrift after they  had completed all of their treatment in the sense that they were no longer having the same level of interaction with the clinicians, with doctors and nurses, that many of their family and friends thought that they should be better because their treatment is finished and they didn’t feel better, they were fatigued, they still were suffering other symptoms and it was difficult to easily move into returning to all of their responsibilities and the kind of things, valued activities in life. This has been recognised and I think more programmes have been developed for women to help them to transition more smoothly to survivorship.