Questions & Answer

Q: What is "Chemobrain"?

A: Dr. Mary Louise Keohan, Memorial Sloan-Kettering Cancer Center

The treatment of cancer has been associated with alterations in patient’s emotional and cognitive functioning. The term “chemobrain” has been coined to describe some of the immediate and long term reported effects associated with chemotherapy. However the true relationship between treatment and reported declines in cognitive function has not been clearly established. There has been a paucity of well designed prospective studies of this “phenomenon”. In order to define the affect of chemotherapy on emotional and cognitive function it is imperative to establish pretreatment measures of neuropsychologic functioning. Once objective measures of a patient’s pretreatment are obtained then longitudinal data assessing real time and long term effects may be studied. As public awareness and concern for chemobrain emerges the identification or dispute of this phenomenon must be appropriately addressed.

There have been several retrospective studies of women receiving adjuvant therapy for breast cancer. The study of Christina Meyer and her colleagues report on a cohort of women with primary breast carcinoma and no evidence of metastatic disease. What is surprising is that 35 % of the patients studied were cognitively impaired. No patient had a history of a previous or current psychiatric or neurologic disorder and no patients were receiving treatment with any agent believed to affect cognition such as steroids, antiemetics or narcotics. Eighty four patients participated in the analysis. 40% of women were premenopausal at the time of neuropsychologic evaluation, 2% surgically induced menopause and 48% postmenopausal. The use of hormone replacement therapy (HRT) was also tracked and available for 67 of 84 patients. 55% reported no prior or current use while 45% had previously used HRT. Prior to the initiation of chemotherapy, 35% of the patients tested showed impairment in the Overall Cognitive Function Index (OCFI). Several cognitive measures were assessed with a significant impairment reported for verbal learning, verbal memory, psychomotor processing speed and attention. Symptoms of anxiety and/or depression (mild to moderate) were reported by 26% of the patients. Analysis of this cohort found an association with cognitive impairment. There were no significant differences in age or education among those showing impairment according to the OCFI and those without OCFI. Nearly twice as likely to be cognitively impaired were women who were postmenopausal, no history of HRT use or had undergone a lumpectomy/mastectomy.

This above referenced study is an impressive start. It addresses and quietly illuminates the powerful impact of hormones, which raises additional questions regarding gender differences and potential impact on adolescents and young adult cancer survivors. Only in time, with well designed longitudinal studies, might one better understand the reported “phenomenon” of those undergoing treatment. While one awaits additional confirmation of such findings, the proven role of adjuvant therapy in the treatment of some malignancies should take precedence over concern for chemobrain.

Reference

Christina Meyer et al, “Chemobrain in breast carcinoma?”, Cancer Vol. 101, Issue 3, pp. 466–475.

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