I was in a similar situation, my disease was limited to my rectum. The colon appeared fine. But both had to go in order to give me a better chance of living healthy. I also know how hard these decisions are and think you are wise to do your research. You will know when it's time for a change.
dx proctitis in 1987
dx UC in 1991, was stable until 1998
1998 started prednisone, asacol, pentasa, nortriptylene, ativan, 6MP, rowasa enemas and suppositories, hydrocortisone enemas, tried the SCD diet, being a vegetarian, omega 3s, flax, pranic healing, yoga, acupuncture, probiotics
2000 lost all my B-12 stores and became anemic
2001 opted for j-pouch surgery- now living life med-free