Cancer treatment carries 'risk of mental problems'

More than a million people in the UK who have undergone treatment for cancer may be at increased risk of cognitive problems.

More than a million people in the UK who have undergone treatment for cancer may be at increased risk of cognitive problems.

Researchers have found that cancer survivors are twice as likely to have difficulty performing certain mental tasks following treatment as those who have never had cancer.

Previous research has suggested that chemotherapy, the use of toxic doses of drugs to kill cancer cells, could have a damaging effect on mental processes.

The latest study, which compared 702 sets of twins, one half of whom had had cancer, found long-term cancer survivors were at increased risk. The twins were selected from the Swedish twin registry and set mental tasks to perform. By studying twins, the researchers eliminated the influence of genetic and early childhood causes of cancer and cognitive defects.

Participants were scored on a scale from zero to three, and anyone having verbal, orientation or recall problems that interfered with daily life was considered to have cognitive dysfunction. The results, published in the Journal of the National Cancer Institute, show that 15 per cent of the cancer survivors had cognitive dysfunction.

Beth Meyerowitz, professor of psychology at the University of Southern California, one of the team of American and Swedish researchers, said: "The twin who had cancer was more likely to have some sort of cognitive dysfunction."

The researchers also found a doubled risk of dementia among the cancer survivors but the result was not statistically significant.

An editorial in the Journal urges a cautious interpretation of the research pending further studies. But Professor Meyerowitz said: "If five, eight or ten years down the line having had that treatment is going to increase a person's risk of dementia, that is something that should be considered by the physician and the patient.

"Maybe a lower dose might be useful for the cancer, but would reduce the risk of cognitive dysfunction."

Professor Lesley Fallowfield, of Cancer Research UK, says: "Although this is an interesting study, the accompanying editorial does urge a cautious interpretation of the results. This is certainly not a reason for cancer patients to panic and refuse treatment."