The Effects of Chemotherapy on Cognition

Official Title

A Prospective Dose-Response and fMRI Study of the Effects of Chemotherapy on Neural Function in Early-Stage Breast Cancer Patients


Many cancer patients who have received chemotherapy experience some changes in their mental functioning.  They refer to this as "chemo fog" or "chemo brain".  This study is being done to further examine how chemotherapy affects brain function and mental processes by comparing brain function in women with breast cancer who are undergoing chemotherapy to women without breast cancer.

Cognitive, emotional, hormonal, and hemoglobin status will be measured at multiple timepoints over the course of chemotherapy and again one year following completion of chemotherapy.  These data will come from standardized psychological tests of cognitive functioning, standardized mood and symptom questionnaires, and laboratory analyses of saliva samples. Some participants will also have their brain structure and function measured at 3 time points using fMRI (funtional Magnetic Resonance Imaging).

Trial Description

Cumulative research leaves little doubt that cancer patients who have been exposed to chemotherapy are at higher risk for subtle cognitive dysfunction than healthy individuals or cancer patients who did not receive chemotherapy.  However, much remains to be explained in this area, including the causality and mechanism of the chemotherapy-cognition relationship. 

The current study will address these outstanding issues by examining changes in neural structure and function over the course of chemotherapy in women with early stage breast cancer, and relating them to changes in levels of hemoglobin, estrogen, and cortisol.  The current study will also determine if changes in cognition, brain activation, and brain structure are enduring, and if they are related to exposure to adjuvant hormonal therapy. 

This study builds on previous research by using: 1) a novel (“dose-response”) study design to establish if there is a causal relationship between chemotherapy and cognitive dysfunction; 2) more targeted, sensitive, and sophisticated cognitive testing methods than have typically been employed; 3) fMRI to provide a window into brain structure and function; and 4) measurement of estrogen, cortisol, and hemoglobin levels throughout the study in an effort to determine if they mediate the relationship between cancer treatment and cognitive disturbance. 

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Canadian Cancer Society

These resources are provided in partnership with the Canadian Cancer Society