Cancer Treatment Related Changes in Cognitive Function:

"Chemo Brain" in Sarcoma Patients and Survivors

Over the past several years the phenomena of changes in mental functioning noticed by people who have received treatment for cancer has been increasingly the topic of blogs,9 chat rooms and has lead to clinical research. Due to the distressing nature and impact of cognitive changes, people have sought information to better understand the cause and to determine potential interventions that could alleviate this distressing symptom.

The terms "chemo brain" or "chemo fog" are words that have been used by patients to describe changes in memory, attention, concentration, and ability to perform mental tasks (like making decisions or reading).6 These changes have often been associated with receiving chemotherapy. However, there are data to support that even prior to starting treatment there may be changes in cognitive functioning. A study published in 2005 found that prior to the initiation of treatment, women experienced a loss of the ability to concentrate.5 Additionally, there have been reports that perceived changes in cognitive functioning may persist for several years following treatment.8 There continues to be a need for research to identify those who are at risk of developing cognitive changes during treatment for cancer as well as research to identify what treatments may increase the potential for the development of loss of cognitive function.

There has been research exploring potential interventions to improve cognitive functioning in patients with cancer. Kohli el al, at the recent meeting of the American Society of Clinical Oncology (2007) reported results of their study of modafinil (Provigil®) as a cognitive enhancer that could potentially improve memory and attention.7 They studied 68 women who had completed chemotherapy for breast cancer and who had evidence of cognitive changes. The results of this randomized study showed that modafinil provided significantly greater improvement in attention and speed of memory in women receiving treatment than those receiving placebo. While the authors noted that this was a small study and further research is needed, this provides preliminary information to guide further research into the potential benefits of this class of drugs, psychostimulants, in alleviating symptoms associated with post treatment cognitive changes.

Research into a non-pharmacologic intervention for the management of changes in cognitive function has been conducted and published.2 This worked is based on an understanding that having the capacity to focus attention is a major component of effective cognitive functioning.1 An ability to focus is critical to being able to acquire information, make decisions, and to carryout activities necessary to care for one self.3 This non-pharmacologic strategy involves an environmental intervention that has shown an ability to restore attention in women with breast cancer. In a randomized study of 157 women newly diagnosed with breast cancer, 83 women were assigned to the experimental invention and 74 were in the non-intervention group.4 Those who engaged in the environmental intervention had greater recovery of capacity to direct their attention from pretreatment as compared with the non-intervention group. This intervention of a home-based program consisted of exposure to a natural environment for 120 minutes per week. There were 3 main components of the intervention. The first component involved an explanation of the restorative experience. Each participant was given background information about activities that have been shown to help rest and restore concentration and mental energy. The restorative activity was described as one that can:

  • Catch your interest easily
  • Involve a change from daily routines or concerns
  • Not be boring
  • Be enjoyable or at least pleasing

Secondly, women in the intervention arm were given a list of potential activities and were asked to select preferred activities that they thought would fit the criteria above and that they would be able to engage in for 120 minutes per week. They were encouraged to select activities that were within their physical capabilities. The suggested activities involved nature in some way and included such things as:

  • Visiting a scenic spot (observing, sitting, strolling)
  • Sitting by a window with a natural view (trees or garden)
  • Watching birds or wildlife
  • Listening to birds or sounds of nature
  • Watching a sunset or clouds
  • Tending to plants or gardens

The third component was making a plan to spend time doing the activity. It was recommended that the time be spaced out over the course of the week into 30 minute increments four times per week. Attention was measured using standard, validated testing tools for determining ability to concentrate. Cimprich concluded, "Importantly, over time, engaging in natural restorative activities supports reflection that involves 'clearing the head' of unfinished thoughts and interactions, making sense of events, and confronting nagging or painful problems. The overall benefits of regular interactions with the natural environment are a rested attentional capacity and improved mental clarity.4"

To date, most of the research related to cognitive function changes in people with cancer has been conducted in women diagnosed with breast cancer. There is no research specifically addressing the experience of patients diagnosed with sarcoma and receiving treatment for sarcoma. From anecdotal reports, patients with sarcoma have relayed similar experiences regarding changes in cognitive function. They too have reported inability to concentrate and carry out tasks that require mental energy.

There continues to be a need for further research.10 Given the low potential for side effects associated with engaging in a restorative intervention in a natural environment and given the potential for benefit, engaging in a restorative activity for 30 minutes four times per week could prove beneficial for those with sarcoma experiencing cognitive changes. As with any new activity, you should be sure to discuss this with your health care professional to ensure there are no limitations your condition may warrant.

Some Additional Resources

Cavaliere, Robert and Shiff, David, "Neurologic Toxicities of Cancer Therapies", Current Neurology and Neuroscience Reports, V 6, N 3, May 2006, pp. 218-226. 

Mayo Clinic Staff, "Chemobrain: When cancer treatment disrupts your thinking and memory", October 2006. 

Raffa, R. B., et al, "Is ‘chemo-fog’/‘chemo-brain’ caused by cancer chemotherapy?", Journal of Clinical Pharmacy and Therapeutics (2006) 31, 129–138. 

Silverman, Daniel H., et al, "Altered frontocortical, cerebellar, and basal ganglia activity in adjuvant-treated breast cancer survivors 5–10 years after chemotherapy", Breast Cancer Research and Treatment, V 103, N3, July 2007, pp. 303-311.

Vardy, Janette and Tannock, Ian, "Cognitive function after chemotherapy in adults with solid tumours", Critical Reviews in Oncology/Hematology, V 63, n 3, September 2007, pp. 183–202. 

Vardy, Janette et al, "Evaluation of Cognitive Function Associated With Chemotherapy: A Review of Published Studies and Recommendations for Future Research", Journal of Clinical Oncology, V. 26, N. 17, June 2007, pp. 2455-2463.

Last revision and medical review: 08/2007

by Denise Reinke, APRN, BC, AOCN
Oncology Nurse Practitioner, Sarcoma Program
University of Michigan


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2. Cimprich, B., Development of an intervention to restore attention in cancer patients, Cancer Nursing, 1993: 16(2) 83-92.

3. Cimprich, B. Symptom management: loss of concentration, Seminars in Oncology Nursing, 1995: 11(4) 279-288.

4. Cimprich, B, An environmental intervention to restore attention in women with newly diagnosed breast cancer, Cancer Nursing, 2003: 26(4) 284-292.

5. Cimprich, B., So, H., Ronis, D., and Trask, C., Pre-treatment factors related to cognitive functioning in women newly diagnosed with breast cancer, Psycho-Oncology, 2005: (14) 70-78.

6. Hamilton, S, Care During Chemotherapy and Beyond: Chemo Brain, Cleveland Clinic Foundation,, 2005.

7. Kohli, S., Fisher, G., Tra, Y., Wesnes, K., and Morrow, G. The cognitive effects of modafinil in breast cancer survivors: a randomized clinical trial. Journal of Clinical Oncology, 2007 ASCO Annual Meeting Proceedings, Part I, 2007: 24 (abstract number 9004).

8. Schagen, S., Muller, M., Boogerd, W., Rosenbrand, R., van Rhijn, D., Rodenhuis, D. and van Dam, R., Later effects of adjuvant chemotherapy on cognitive function: a follow-up study in breast cancer patients, Annals of Oncology, 2002: (13) 1387-97.

9. Sievers, L. NPR Blog, My Cancer, The Fog and Fatigue of 'Chemo Brain'

10. Tannock, I, Ahles, T., Ganz, P and van Dam, F. Cognitive impairment associated with chemotherapy for cancer: report of a workshop, Journal of Clinical Oncology, 2004: 22(11) 2233-2239.