Proctitis

Why can't the just remove the rectum alone?

Well I thought you had to have the whole
Colon removed, proctitis is just in the rectum

Ok :)

My last scope showed no visible signs so they had to wait for biopsy to confirm mild inflammation.. I had bleeding, pus at time of scope

I think UC generally involves the whole colon at one point or another, whether it is visible or not. Sometimes people can jump right on treatment and contain it only in the rectum or can use treatments to heal the colon, with the rectum making the last stand. My opinion of proctitis is that that is just where your UC happens to be at the moment (at least the visible signs). In other words, I think doctors would not take out the rectum only because they believe that without the rectum to fight anymore, the whacky immune system would then just move up to where it could attack and you would be back to square one all over again. UC is an autoimmune disease where your immune system is going haywire. It is not a disease like cancer where you can just cut out the affected areas and be done with it (if you get it all).

It would probably be like it is with CD, when you remove the inflamed part that's still attached to another part that is also vulnerable to getting inflamed (due to it being the nature of the beast) then the part(s) left behind will more than likely be affected at some point as well, that's the difference with UC and getting the colon and rectum removed putting an end to UC, but it wouldn't put an end to those with CD unless you took out the entire GI tract because UC is limited and CD can affect the entire GI tract.