Patients with ulcerative colitis are at increased risk of colorectal cancer.
It is widely believed that this is secondary to colonic inflammation.
However, the severity of colonic inflammation has never been shown to be a risk factor.
In this study, doctors from England examine various potential risk factors for neoplasia in patients with long-standing ulcerative colitis.
They matched 68 cases of colorectal neoplasia 2 control patients from the same surveillance population.
Matching was for sex, colitis extent, age at onset, duration of colitis, and year of index surveillance colonoscopy.
The doctors recorded segmental colonoscopic and histological inflammation using a score system, where 0 was normal and 4 was severe inflammation.
They also collected data on history of primary sclerosing cholangitis, family history of colorectal cancer, smoking, and drug history.
The doctors found a significant correlation between colonoscopic (OR 2.5) and histological (OR 5.1) inflammation scores and the risk of colorectal neoplasia.
However, multivariate analysis determined that only the histological inflammation score was significant (OR 4.7).
Dr Matthew Rutter's team concluded, "In long-standing extensive ulcerative colitis, the severity of colonic inflammation is an important determinant of the risk of colorectal neoplasia".
"Endoscopic and histological grading of inflammation could allow better risk stratification for surveillance programs".