November 30, 2006

Study Says Chemotherapy Kills Healthy Brain Cells

New research by the University of Rochester Medical Center has found that chemotherapy drugs may be harmful to healthy brain cells.

The results, which also indicate that chemotherapy may cause long-term brain damage, represent the closest that scientists have come to pinpointing the underlying cause of "chemo brain," a common side effect of cancer treatment.

Cancer patients who receive chemotherapy have long complained of adverse neurological side effects ranging from memory loss, seizures, vision loss and even dementia. A study earlier this year suggested that upwards of 82% of cancer patients reported that they suffer some form of cognitive impairment.

The research team exposed healthy brain cells as well as cancer cell lines to three commonly used chemotherapy drugs carmustine, cisplatin, and cytosine arabinoside.

They discovered that exposure levels typically used when treating patients killed 70-100% of neural cells but just 40-80% of the cancer cells. In animal models, several types of healthy cells continued to die for at least six weeks after treatment.

Scientists speculate that there are two possible ways the destruction of these healthy cells result in cognitive problems. First, they believe that cell division that occurs in the hippocampus is essential to learning and memory. Hence, the cognitive side effects of chemotherapy could potentially be traced to the drugs' disruption of the process of cell division in this particular region of the brain.

Additionally, the research showed that the chemotherapies destroy a specific cell type, called oligodendrocytes that help signals in the nervous system move rapidly from one point to another.

The scientists said this new research points to several potential strategies to prevent cell destruction, ranging from application of protective agents to understanding why some people are spared neurological side effects while others are not.

Additionally, the approach used in the study could serve as a screening method to analyze the effectiveness of new cancer therapies to determine which cell populations are at risk during treatment.