[m0llusk]

This is a very complex subject because the sensitivity of tests for colorectal cancer has improved over time and more testing is being done. This makes it appear as if there is a great increase in colorectal cancer when there really isn't.

A very interesting related study has become known as "The Norwegian Colorectal Study" found that early testing was a waste of money since only those with a family history of colorectal cancer or IBS symptoms or both actually got colorectal cancer before 55. For most people the polyps which are precursors to colorectal cancer do not appear before age 55. That means that the current push for aggressive testing starting at 50 is a distracting waste of time, money, and effort that should be eased back.

[ravel-bar-foo]

There have been some really interesting studies which showed that in order to get colorectal cancer you have to accumulate 4-6 deletrious mutations in the same cells. People with genetic predispositions are born with 2-3 of those mutations. That's why we see this age association. (Just remember being fascinated and thought I would add some context.)