Research Seems to Confirm ‘Chemo Brain’ Syndrome

“I can’t concentrate.” “My mind is foggy.” “I can’t remember things.”

These are common complaints expressed by cancer survivors in support groups, online message boards and doctors’ offices across the country.

Long known to cancer patients who have undergone chemotherapy as “chemo brain” or “chemo fog,” it is a condition of cognitive impairment that has only recently been confirmed by a handful of studies.

In a study published earlier this month, researchers in Toronto found that women who received chemotherapy for early-stage breast cancer (after surgery had removed all known cancer) had decreased ability to remember, think and concentrate when compared to healthy women. The findings--published in the July issue of the Journal of Clinical Oncology--should not be viewed as a reason for withholding chemotherapy, a proven treatment that markedly improves cancer survival rates, said Dr. Ian F. Tannock of the University of Toronto, one of the study’s investigators.

But patients and their doctors need to be aware of the side effects of chemotherapy, he added.

Most women diagnosed with early-stage breast cancer receive chemotherapy as part of their treatment. In California, about 22,000 women were diagnosed with early-stage breast cancer in 1996.

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Unlike chemotherapy’s better-known side effects, such as nausea, vomiting, fatigue, hair loss and changes in menstrual cycles, much less is known about cognitive difficulty because fewer studies have looked at the subject.

The Canadian study involved 31 breast cancer patients receiving standard-dose chemotherapy, 40 breast cancer patients who had undergone chemotherapy at least a year ago and 36 women who were cancer-free.

All 107 women underwent a battery of exams to test their neurological and psychological faculties: memory exercises, drawing shapes and figures, and performing simple tasks like naming words beginning with the letter “T.”

The overall scores of women who were receiving chemotherapy were significantly poorer than those of healthy women. The differences could not be explained by age, education level, menstrual phase or mood disturbances--all factors known to influence cognitive ability.

Significantly more women from the two groups of breast cancer patients had moderate or severe cognitive impairment than the healthy women.

In addition, lingering cognitive problems were found up to a year after treatment, although the results were not statistically significant, the study found.

Experts agree that these findings are consistent with previous studies.

“This important data joins a small body of research on an issue that [researchers] need to pay attention to,” said psychologist Julia Rowland of the National Cancer Institute.

Dr. Harmon Eyre, medical director of the American Cancer Society, said the study results give patients another side effect to consider when evaluating whether to undergo chemotherapy.

Although more subtle than the physical side effects of chemotherapy, cognition difficulties can affect an individual’s quality of life as well as career and educational choices, especially if the problem persists.

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Patients may not be able to think clearly or perform simple tasks like remembering the items on a grocery list.

“Some patients experiencing cognitive problems have chosen not to finish school or have shifted to a less demanding job,” said psychologist Tim A. Ahles of Dartmouth Medical School in Hanover, N.H. He estimates that 20% to 30% of cancer patients who have chemotherapy continue to have cognitive impairment more than two years after treatment.

“More patients may experience cognitive problems during chemotherapy, but some will recover to pre-treatment levels of cognitive functioning,” said Ahles, who has studied the long-term effects of chemotherapy.

Both study investigators and experts recognized two limitations of the Toronto study: the small number of patients studied and the use of a comparison group of healthy women.

The stress and anxiety of being diagnosed with cancer alone could disrupt cognitive acuity, experts say.

Although the study investigators stress that this is a preliminary study, the results could have implications on informed consent, counseling and psychosocial support.

Chemotherapy patients “need to be aware that there are ways for them to be supported and helped by teaching coping skills,” said Dr. Christine B. Brezden of the University of Toronto, lead investigator of the study.

Other experts say the findings may also impact decisions as to whether to choose aggressive treatment when chemotherapy promises only slight improvement in a patient’s chance of survival.