Generally speaking, proctitis patients have the best prognosis of all ulcerative colitis patients. They have the least risk of their UC spreading, and no significant increased risk of colorectal cancer (unlike proctosigmoiditis and pancolitis patients). That said, there's a few posters here who did start with proctitis and now have pancolitis. Let's throw some statistics at it:
webmdguidelines.com said...
If ulcerative colitis is initially limited to the rectum (proctitis) at the time of diagnosis, fewer than 30% of individuals will go on to develop more extensive disease (Rowe). Approximately 10% of patients presenting with proctitis will develop a pancolitis (Rowe).
On average, individuals with ulcerative colitis have a 50% chance of having their next flare within 2 years (Rowe).
The majority of individuals who advance to more extensive disease will do so within the first 5 years after diagnosis (Rowe).
www.mdguidelines.com/ulcerative-colitis
So there's 70 percent odds that your proctitis won't spread. There's 90 percent odds you won't get pancolitis. UC is particularly aggressive within the first 5 years, so if you can get through that, then you have better still odds.
Every case is individual, so sometimes we're the unlucky dude/dudette? who falls within that less than 10% odds.