Cancer survivors are more likely to suffer difficulties with mental tasks than people without cancer, according to the June 1 issue of the Journal of the National Cancer Institute. Researchers at the University of Southern California studied Swedish twins aged 65 and older. They compared mental tasks in each pair. One twin had been diagnosed with cancer and the other had not. The researchers write that previous studies have shown that cancer survivors often experience a decline in mental tasks, but it remains “unknown how long these deficits last or whether they worsen over time.