Comparison of Colon Adenoma Detection Rate Using Two Distal Colonoscope Attachments

Although mortality from colon cancer is decreasing, it remains the second leading cause of
cancer related death in the United States. There are multiple factors contributing to this
decrease, such as increased awareness, improving screening techniques, etc.

Of the available modalities approved for colon cancer screening in the United States,
colonoscopy is considered the gold standard. Colonoscopy has the advantage of being both
diagnostic and therapeutic, allowing the removal of pre-cancerous polyps, before the polyps
can transform into cancer. Colonic polyps can occur at any location from the rectum to the
cecum. Colonoscopy has been shown to be more effective in decreasing incidence of cancer in
the left colon but remains limited in the detection of right sided polyps /lesions 2. This
difference based on location is thought to be due to several reasons. Typically the right
side of the colon is less clean than the left side during colonoscopy, thereby impairing
visualization of polyps. This problem has been overcome by incorporating a "split bowel
preparation", which has not become standard of care. However, the problem of not being able
to visualize polyps behind folds seen in the colon persists despite improvements in the
quality of cleansing of the colon. Various endoscopic technologies have been introduced with
the goal of assisting with the manipulation of such colonic folds, and thereby reducing
chances of missing polyps behind fold. Two such colonoscope assisted devices including the
distal transparent cap and the Endocuff endoscopic overtube.

The Endocuff overtube is a small device with flexible arms arranged in 2 rows. Each row has
8 short, soft arms projecting away from the device. These arms are used to peel back the
colonic folds without causing physical damage to enable visualization behind colonic folds.
The use of Endocuff overtube has shown promising results in terms of cecal intubation rate
and time as well as adenoma detection rates 3.

The transparent cap attachment is a clear plastic device that fits at the end of the
colonoscope and extends a short distance past the tip of the colonoscope. It aids in the
manipulation of folds and in maintaining a suitable distance from the mucosa, with the goal
of improving visualization. Although some studies comparing cap fitted colonoscopy to
standard (non- attachment) colonoscopies have shown improved adenoma detection 4, others
have shown no significant benefit 5.

Although, these devices have been compared with conventional colonoscopies (i.e without any
distal attachment), to the investigator's knowledge, there are currently no studies that
have compared these two distal colonoscope attachment devices head-to-head, and none has
specifically evaluated effects on detection of right sided adenomas. Also, here at UCDavis,
these devices are being used specifically in diagnostic colonoscopies for removal of large
polyps and the choice of which specific device is used dependends on level of comfort of the
advanced endoscopist. The endoscopists participating in the investigators' study do not
currently use these devices as part of their routine colonoscopies, thus it is important to
provide head to head comparison of these devices to help guide management practice.

Therefore, the investigators' goal is to compare the Endocuff overtube assisted, transparent
cap fitted, and non-cap fitted ( standard) colonoscopy in patients presenting to UC Davis
Medical Center for screening colonoscopies.

In addition, 2 of the 3 investigators will employ the water exchange method during for all
arms of the trial, while the other investigator will employ the conventional air method of
colonoscopy.

Inclusion Criteria:

All patients >/= 50 years of age, presenting for a screening or surveillance colonoscopy
at UC Davis Endoscopy Suites

Exclusion Criteria:

i) Age less than 50 (ii) Prior history of colon cancer (iii) Patients with inflammatory
bowel disease (iv) Patients suspected to have colon cancer based on non invasive tests
such as stool tests for hemoglobin or DNA, or imaging finding suggestive of colon cancer
(CT or barium enema).

(v) Patients undergoing colonoscopy for evaluation of symptoms such as abdominal pain,
rectal bleeding, diarrhea, constipation, etc, or patient with iron deficiency anemia
suspected to be due to ongoing bleeding inside the colon (vi) Patients with family history
of colon cancer in 1st degree relative below the age of 60 (vii) Patients with family
history of hereditary polyposis syndromes such as Lynch syndrome, familial adenomatous
polyposis etc, which are associated with an increased risk of colon cancer (viii) Patients
unable to consent (ix) Pregnant patients (x) Incarcerated patients (xi) Non-English
speakers