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Vol. 66, No. 4 2015
Northeast Florida Medicine
DCMS online
. org
Inflammatory Bowel Disease
Out with the Old and In with the New?
The Changing Approach to Colorectal Cancer
Surveillance in Ulcerative Colitis
By Michael F. Picco, MD, PhD, FACG
Introduction
Ulcerative colitis (UC) and Crohn’s disease are chronic
inflammatory bowel diseases. Ulcerative colitis only affects
the colon, while Crohn’s disease may involve any portion of
the tubular digestive tract. Significant colonic involvement by
either of these diseases increases the risk of colorectal cancer
(CRC). Unlike sporadic colon cancer, the classic adenoma
cancer sequence does not occur in the development of col-
orectal cancer associated with UC. UC-related colorectal
cancer (CRC) develops in a background of inflammation and
regeneration.
1,2
Unlike the adenoma precursor in sporadic
CRC, the precancerous lesion in UC is cellular dysplasia
arising from flat mucosa which may not be readily seen by
standard white light colonoscopy.
Conclusions related to ulcerative colitis, also apply to
colonic Crohn’s disease. With the advent of newer, more
effective treatments for these diseases, surgery is becoming
less common so that many patients with significant colonic
involvement will delay, if not avoid, surgery. The risk of
colorectal cancer in these patients increases with time so
effective surveillance programs are essential. Recent advances
in image enhancing colonoscopyhave revolutionized the field.
What are the risks for colorectal
cancer in chronic ulcerative colitis?
Early studies suggested that the risk of CRC in UC was
about six times that of the general population.
3
However,
a more recent meta-analysis concluded that the risk is
half as much.
4
The reasons for this difference may be due
to selection bias (i.e. referral based vs. community based
populations), better medical therapies, and better methods
of dysplasia detection. Understanding individual patient
risk has shaped surveillance programs. The most important
risk factors for CRC in UC are disease duration, anatomic
extent of the disease, and presence of primary sclerosing
cholangitis. (Table 1) Patients with additional risk factors
of family history of CRC, presence of pseudopolyps, and
greater severity of inflammation may also benefit from
more intensive surveillance.
5
Address correspondence to:
Michael F. Picco MD, PhD, FACG
Chair, Division of Gastroenterology
Consultant and Associate Professor of Medicine
Mayo Clinic Florida
4500 San Pablo Road
Jacksonville, FL 32224
Abstract:
Colorectal cancer risk is high among patients with
chronic long-standing extensive ulcerative colitis or colonic Crohn’s
disease. The typical or conventional method of dysplasia detection is
with white light colonoscopy. There have also been major advances
in the field of image-enhanced colonoscopy with chromoendoscopy.
Chromoendoscopy is a technique where either indigo carmine or
methylene blue dye is sprayed on the colon during colonoscopy. This
method has dramatically improved dysplasia detection. A recent
international consensus conference called for the implementation of
chromoendoscopy more broadly, especially for high-risk individuals.
However, controversy exists as to the significance of dysplasia found
with chromoendoscopy and which high risk patients are more likely
to benefit from the technique.
Table 1. Risk Factors for
Colorectal Cancer in Ulcerative Colitis
Major Risk Factors
Extent
Pancolitis>>Left sided colitis>>>
proctitis/proctosigmoiditis = non-colitis population
Duration >8 years
Primary Sclerosing Cholangitis
Minor Risk Factors
Family History of Colorectal Cancer
Persistent Active Inflammation of the colon
Pseudopolyps (Inflammatory polyps)