]' The Mamma Mia star said she thought doctors must have been mistaken when she first heard the news. 'Roles that require me to be blubbing all the time, or mourning somebody, take a lot out of you. 'I can't blame all of that on cancer. ' Bowel, or colorectal, cancer affects the large bowel, which is made up of the colon and rectum. Extreme, unexplained tiredness• She remembers telling her husband Grant Roffey.