Risk from ulcerative
colitis
Several studies have indicated
that patients with ulcerative colitis have a 2-8.2 relative risk of colorectal
cancer compared with the normal population, accounting for about 2% of
colorectal cancers. One of the factors influencing an individual’s risk
is duration of colitis—the cumulative incidence of colorectal cancer is
5% at 15 years and 8-13% at 25 years. The extent of disease is also important:
patients with involvement of right and transverse colon are more likely
to develop colorectal cancer (the relative risk in these patients is 15
compared with the normal population). Coexisting primary sclerosing cholangitis
independently increases the relative risk of ulcerative colitis associated
neoplasia (UCAN) by 3-15%. In addition, high grade dysplasia in random
rectosigmoid biopsies is associated with an unsuspected cancer at colectomy
in 33% of patients.
Molecular basis of adenoma
carcinoma sequence and UCAN
Cancers arising in colitis versus those in adenomas Important clinical
and biological differences exist between the adenoma carcinoma sequence
and ulcerative colitis associated neoplasia. Firstly, cancer in ulcerative
colitis probably evolves from microscopic dysplasia with or without a mass
lesion rather than from adenomas. Secondly, the time interval from the
presence of adenoma to progression to carcinoma probably exceeds the interval
separating ulcerative colitis associated dysplasia from ulcerative colitis
associated neoplasia. Thirdly,
patients with a family history
of colorectal cancer (but not ulcerative colitis associated neoplasia)
and who also have
ulcerative colitis are at
further increased risk, suggesting additive factors.
Prevent and Heal ulcerative colitis
: http://colitis-boswellia.com/
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