Colon removal as cancer-prevention?

In long-standing UC, some doctors advocate colon removal after 20-30 years on the grounds that there is no guarantee that even annual and extensive colonscopies can catch dysplasia prior to cancer developing.  So, why doesn't this same advice apply to Crohn's that includes extensive involvement of the colon?  Are Crohnie's simply supposed to put up with a higher cancer risk than UCers after so many years (assuming this medical logic is sound).  My UC is somewhat indeterminate and I assume Crohn's colitis, if it actually is that (officially it is still labelled UC) has an identical risk for cancer as UC.  Also, I notice that Crohnies rarely get jpouches - as opposed to permanent ileos- even if they have Crohn's colitis.  Not sure why this is so- seeing as there seems no guarantee the pouch will get crohn's- and if it does, the pouch can be reversed.  So I wonder why the jpouch isn't done more for crohn's colitis.

Well I'm going to make a guess here. One factor would likely be that Crohns affecting primarily rhe colon (with overall colon involvement like in UC) is pretty rare. A second would be that since Crohns, even in the colon, has intermittent inflammation with skip areas that it is easier to biopsy those affected areas to monitor for dysplasia. And finally I am not sure that total colectomy is often suggested in UC primarily as a cancer prevention surgery; more often it is seen as curative when all meds fail to control symptoms, more a quality of life than a death prevention matter. Finally, everything I have seen through the years shows that while there is a slightly elevated colon cancer risk from longstanding Crohns with colonic involvement, that risk is statistically higher in UC.