Perhaps this is enough justification for us men to avoid these procedures:
When you put everything together, including the fact that colonoscopy is itself not without risks, I think my avoidance of my doctor’s invitation [to a colonoscopy] might not be quite as absurd as it appears. It is true that, if everyone had colonoscopy, many but not all deaths from colorectal cancer might be prevented; but I am only one person, as is everyone else, and so the chances of it saving my life, or the life of any individual person, are very small.