Chemotherapy 'harms brain function'

Chemotherapy drugs may affect the brain

Life-saving anti-cancer drugs could be leaving patients unable to think clearly, according to researchers.

And the effect may be persisting beyond the end of their treatment courses.

I think the important thing is at least to alert people that it occurs, not to scare them that they shouldn't have this therapy

Dr Ian Tannock

The study looked at 107 women who were either receiving chemotherapy for breast cancer, had received the drugs a few years earlier, or who were healthy.

The "thinking power" of the brain, or cognitive function was measured.

This meant their memory was impaired, as was the ability to remember, think and concentrate.

The group of patients currently receiving the drugs had significantly lower scores.

Even the group who had received the therapy some time before performed worse in general, although the numbers in this group were not large enough to make it statistically significant.

Dr Ian Tannock, who led the study at Princess Margaret Hospital in Toronto, is now planning larger studies to test for the persistent cognitive impairment.

"No complete improvement"

He said: "Our hypothesis is that the deficits gradually but not completely improve.

"I think the important thing is at least to alert people that it occurs, not to scare them that they shouldn't have this therapy, because it's obviously very important for their long-term survival."

It is not known how exactly the chemotherapy drugs have an effect on the brain.

They have a pronounced effect on many body tissues, particularly those which grow or divide quickly, such as those in the hair follicles or stomach lining.

However, it was believed that they could not pass the "blood brain barrier" protecting the brain tissues.

Professor Peter Maguire, from the Cancer Research Campaign's Psychological Medicine Group, said that other studies had pointed to chemotherapy drugs having this effect on cognitive function.

However, this was thought to be a temporary, he said, or at least, if permanent, a "very subtle" effect.

He said: "In most people, you expect this cognitive impairment to go once the treatment ends."

He said that, although research suggested that it was the drugs rather than anxiety or stress that was causing the mental problems, the worries of cancer diagnosis could have an extra effect on the mind.

The research was published in the Journal of Clinical Oncology.