I've had this for almost 4 years, starting 5 months after RT.
In my case it's painless, doesn't cause incontinence, and not bad enough to cause anemia, and has no impact on QoL, so I was told it was harmless and didn't need treating unless I particularly wanted it treating. They did check to see it wasn't bowel cancer. I tried a steroid foam enema, but it didn't do anything. It seems to be reducing in quantity and frequency all by itself over last few months. I've never heard any suggestion proctitis might cause bowel cancer, but I did wonder if it might mask bowel cancer since I'm not going to notice any bleeding from elsewhere.
I did do a FIT test (poo in a stick job). I waited until no visible bleeding for a couple days and the test came back clear, which should have ruled out any additional bleeding further back in my GI tract, which often isn't as visible.