The colon is more susceptible to neoplasia (cancer) than the small intestine due to frequent cell turnover and higher exposure to toxins from the microbiome and gut contents.

“it's not surprising that the colon is so susceptible to neoplasia to the formation of cancer because it has at its surface a cell that turns over so frequently and therefore you probably have more and more chances for genetic errors of replication that produce mutations that are oncologic ... one part of the answer is that microbiome to which the large intestine is exposed as orders of magnitude larger than that of the small intestine and the other part of it is that the products that sit in the lumen of the large intestines sit there from much much longer”