Intestinal Cancer and Crohn’s Disease
The cause of cancer in the intestine is unknown despite extensive and continuing research.
Patients with Crohn's disease of the small and/or large intestine have an increased risk of developing cancer at these sites.
Most patients never develop cancer, but its early detection in patients at increased risk can lead to prompt and curative treatment. The risk should therefore not cause you great concern because if you have had extensive disease for 10 years or more, you will be offered regular screening and monitored very closely.
The risk is related to 2 main factors:
There appears to be some evidence that it occurs more frequently in chronically active disease than it does in previously active or intermittent disease.
Several studies have been carried out to estimate the risk by following patients over a period of 10-40 years. Some failed to show an associated risk, but others predicted an increase which was twice that of the general population for developing colorectal cancer. If the disease is confined to the colon (large intestine), this risk is estimated at around 5 times greater.
The risk of small intestinal cancer has been estimated at around 6 times that of the general population, but as this is an extremely rare cancer in the general population, the risk in Crohn's disease is still small.
(The above figures are only estimates and may vary among different studies according to referral centres and selection biases).
The site and severity of the disease
Cancer of the large intestine tends to occur when the right side of the colon is affected with associated strictures and/or fistulous disease.
Cancer may also be associated with long-standing perianal disease (ano-rectal fistulae, fissures, abscesses) which has not responded to conventional treatment.
What are the signs and symptoms?
Late symptoms may include:
After 10 years of disease, particularly in the colon, such symptoms should be taken seriously and discussed with your doctor.
How may it be detected?
1. Small bowel disease
2. Large bowel disease (unresected)
b) Without anal disease
If there are no strictures present a colonoscopy and multiple biopsies will be offered on a two-yearly basis.
What happens if cancer is detected?
For severe, refractory (not responsive to treatment) perianal disease,
removal of the colon (colectomy) and formation of an ileostomy may be
indicated. A well-functioning ielostomy with appropriate support from
stoma care nurses may be liberating from the misery of persistent fistulae,
abscesses or pain and, thus, improve general quality of life. The fear
of colorectal cancer is also removed.