Here’s vegan Jack Norris RD take on the recent Vegetarians Get Fewer Cancers.
Among vegetarians and people who eat moderate amounts of meat and don’t smoke, cancer rates are about the same, but lower than for people who do smoke and eat large amounts of meat. In other words, you can reduce your risk of cancer by not smoking, by limiting meat to moderate amounts (or abstaining entirely), and by eating plenty of fruits and vegetables. The evidence for stronger claims doesn’t seem to be there.
Similarly, the combined colon cancer rates to date seems to indicate that, in comparison to eating moderate amounts of meat, being vegetarian neither increases nor decreases your risk of colon cancer.