"Chemo Brain"

Chemobrain/Cognitive Dysfunction

Unfortunately, this is indeed quite normal. It is estimated that maybe one in five people who undergo chemotherapy will experience what many cancer survivors frequently refer to as "chemobrain" or "chemofog." Women and men who experience chemobrain typically say that they feel that they are not able to concentrate, have a hard time remembering things, have trouble finding the right word when speaking or writing, or can't multitask the way they used to.

This type of cognitive dysfunction is a problem that cancer survivors have been talking about for years. Only recently, though, have researchers begun studying the impact of chemotherapy on cognitive functioning. But it's not an easy area to study. Part of the problem is sorting out which problems are due to chemotherapy and which are due to having a serious illness like cancer that can result in physical debilitation, depression, sleep disruption, hormone shifts (not just sex hormones, but thyroid, melatonin, etc.), and fatigue--all of which can affect cognitive functioning.

For older women, the impact of chemotherapy may be compounded by the natural aging process, which, in and of itself, can be related to the development of cognitive problems. There is some evidence that verbal fluency and word recall changes for some women but not others as they age and their estrogen levels fall. So it is possible that the problems some women think are due to chemotherapy might just be what they'd be experiencing anyway at their age and stage of life. For younger women, the cognitive side effects related to chemotherapy may be compounded by the fact that chemotherapy can put them directly into menopause, which in and of itself causes hormonal changes that can affect cognitive functioning.

There are a number of theories as to why chemobrain may occur. One is that some types of chemotherapy can cross the blood/brain barrier. Another is that the cognitive problems are created by free radicals, the toxic elements that many types of chemotherapy produce. And yet another is that some people have a genetic background that makes them more susceptible to the effects of chemotherapy. Most likely it is not just one factor but many factors that combine to set the stage for chemobrain to occur. However, we still have a lot to learn before we will be able to explain why this problem affects some people and not others or why these problems persist after treatment stops.

As the search for the cause of chemobrain continues, researchers have begun looking at ways to alleviate its impact. Studies now underway are exploring whether Ritalin, which is used to improve fatigue, or Procrit, which increases red blood cell count to improve energy can improve cognitive functioning. This research is still very preliminary, however, and these drugs should only be used as part of a clinical trial.

You should definitely speak with your doctor about the problems you are experiencing to try to rule out other causes. Your doctor should review with you whether depression, the use of medications that are sedating, or sleep problems that are causing fatigue could be factors in the cognitive problems you are experiencing. Developing coping strategies such as making lists, using a tape recorder or Dictaphone, carrying a personal calendar or diary, or taking notes during conversations can also be helpful.

Doing puzzles to stimulate your mind may be helpful. So can reducing stress--which not only can result from such cognitive problems but can also cause them--may also be helpful. Support groups, meditation, and yoga may offer benefits as well.

References:
Ahles, TA, et al.
Neuropsychologic Impact of Standard-Dose Systemic Chemotherapy
in Long-Term Survivors of Breast Cancer and Lymphoma.
Journal of Clinical Oncology Vol. 20. No 2 (January 15), 2002: 485-93.
Brezden CB, Phillips KA, Abdolell M, Bunston T, Tannock
IF Cognitive function in breast cancer patients receiving adjuvant chemotherapy.
Journal of Clinical Oncology (2000 Jul) 18(14): 2695-701
Ferguson RJ, Ahles TA.
Low neuropsychologic performance among adult cancer survivors treated with chemotherapy.
Current Neurology and Neuroscience Reports 2003 May; 3(3): 215-22.
Freeman JR, Broshek DK. Assessing
Cognitive dysfunction in breast cancer: What are the tools?
Clinical Breast Cancer 2002 Dec; 3 Supplement 3: S91-9.
Phillips KA, Bernhard J.
Adjuvant Breast Cancer Treatment and Cognitive Function: Current Knowledge and Research Directions.
Journal of the National Cancer Institute 2003; 95: 190-197.
Schagen SB, van Dam FS, Muller MJ, Boogerd W, Lindeboom J, Bruning PF
Cognitive deficits after postoperative adjuvant chemotherapy for breast carcinoma.
Cancer (1999 Feb 1) 85(3): 640-50

Chemotherapy Impacts Cognitive Functioning Up to Ten Years After Treatment

Standard-dose chemotherapy can negatively impact the cognitive functioning of cancer survivors up to 10 years after treatment, a new study from the Dartmouth-Hitchcock Medical Center finds.

The study -- the first of its kind to compare the neuropsychological effects of chemotherapy and radiation therapy on long-term cancer survivors -- determined that people treated with chemotherapy scored significantly lower on tests for memory, concentration, and psychomotor functioning (ability to integrate different types of information) than patients who received only radiation therapy or surgery. Previous studies have suggested that cancer survivors treated with chemotherapy experience cognitive deficits in the short-term after treatment and up to two years following treatment.

"We wanted to study long-term cancer survivors to see if the secondary effects of chemotherapy on cognitive functioning could be detected many years after treatment and our results suggest that they can," said Tim A. Ahles, Ph.D., lead study author, and Professor of Psychiatry and Program Director of the Center for Psycho-Oncology Research at the Dartmouth-Hitchcock Medical Center. "The cognitive effects of chemotherapy on patients were relatively subtle and most of the scores fell within the normal range of performance. However, patients tell their physicians that these changes are very recognizable."

The 128-person study compared breast cancer and lymphoma survivors treated with chemotherapy (35 breast cancer patients, 36 lymphoma patients) with people who received only radiation therapy or surgery (35 breast cancer patients, 22 lymphoma patients). Study participants were at least five years postdiagnosis, not presently receiving cancer treatment, and disease-free.

Patients were given a standard neuropsychological assessment in nine areas including verbal ability, visual and verbal memory, and motor functioning. Participants also completed questionnaires on anxiety, fatigue, depression, and memory functions.

Results reveal that 85 percent of study participants received only one type of chemotherapy regimen. Survivors who were treated with chemotherapy scored significantly lower on the neuropsychological assessment compared to those treated with only radiation therapy or surgery across multiple domains, particularly in the areas of verbal memory and psychomotor functioning. However, these results, as well as those of other researchers, suggest that only a subgroup of patients experience persistent cognitive deficits post-treatment.

Reports of depression, anxiety, and fatigue, all of which can affect cognitive functioning, did not differ between the groups. This suggests that the differences in performance on the cognitive tests were due to the chemotherapy itself, not to greater levels of depression, anxiety, and fatigue in patients who received chemotherapy.

According to Dr. Ahles, more studies need to be conducted to determine exactly what might be affecting cognitive functioning so researchers can identify types of treatments or cognitive rehabilitation that might help cancer survivors.

Journal of Clinical Oncology
January 15, 2002