POLYP DETECTION WITH THE PEERSCOPE SYSTEM*: A RANDOMIZED TANDEM COLONOSCOPY STUDY

Worldwide, colorectal cancer (CRC) is the third most common cancer in men and
second most common cancer in women, accounting for an estimated total of 1.2
million new cases and 608,000 deaths per year. Colorectal cancer almost always
starts in a benign growth called a polyp. Polyps originate in the inner lining
of the colon, where they may be visible in a screening test known as
colonoscopy. Recent research has shown that appropriate screening and treatment
can alleviate much of the suffering associated with colorectal cancer and
reduce the number of deaths caused by this malignancy.

Colonoscopy is a procedure for viewing the interior lining of the colon using a
flexible endoscope called a colonoscope. Colonoscopy is a key tool for
colorectal cancer screening and diagnosis of different diseases effecting the
colon and ileum. The procedure allows therapeutic interventions such as
polypectomy and biopsy collection. Recent data suggest that colonoscopy is
superior to other screening procedures for the detection of colorectal cancer
in people aged over 50. The American College of Gastroenterology has recently
recommended that individuals over 50 at average risk of colon cancer should
have elective colonoscopy every 10 years, and those at higher risk more
frequently.
Several methods have been used for screening for colorectal cancer, including
fecal occult blood testing, barium enema, flexible sigmoidoscopy, colonoscopy,
and more recently, CT colonography (also known as virtual colonoscopy).
Colonoscopy is currently regarded as the *gold standard* for detection of
polyps and cancers in the colon.However, a growing number of studies have
documented that significant numbers of lesions are missed during routine
colonoscopy.

The primary reason for missing polyps and cancers is thought to be poor
visualization of areas of the colon on the proximal aspects of haustral folds
and rectal valves and behind flexures and the ileocecal valve. These locations
tend to be hidden from the forward-viewing colonoscope and can generally be
seen only through extensive manipulation of the colonoscope in an effort to
flatten or *iron out* folds. Because they require substantial additional time,
such maneuvers are not always performed during routine colonoscopy. Pickhardt,
et al. mapped the locations of nonrectal neoplasms that were missed by
colonoscopy but detected by CT colonography, and found that 67% were located on
the proximal aspect of folds. A recently published, 10,292 person Canadian
study found colonoscopy to have missed about every cancer in the right side of
the colon, where cancers are harder to detect but about 40% arise. The study
also found colonoscopy to have missed roughly a third of cancers in the left
side of the colon. An additional study involving California Medi-Cal patients
found similar results. There is mounting clinical evidence supporting the need
to reduce the *miss rate* of standard colonoscopy.

To compare the additional diagnostic yield obtained by using the PeerScope
System* extended view vs. the diagnostic yield obtained by the Standard view
colonoscopy.
In addition, time measurements including time to cecum, time for withdrawal and
overall procedure time will be analyzed and reported for each group.

Patients who are scheduled for screening, surveillance or diagnostic
colonoscopy will be recruited to the study and randomized to one of two groups.
Each enrolled subject will undergo two *back-to-back* procedures.
Subjects in Group A (study group) will undergo a Standard view colonoscopy
followed immediately by a PeerScope System* extended view colonoscopy. Subjects
in Group B (control group) will undergo a PeerScope System* extended view
colonoscopy followed immediately by a Standard view colonoscopy.
Results from the two groups will be analyzed and compared, with primary outcome
measures being detection rates for total polyps and detection rates for
adenomas. Secondary outcome measures will include withdrawal time, total
procedure time and characteristics of polyps detected, including size and
histological results.
Subjects will be followed through a 24 hour and a 7-days telephone interview
for analysis of unexpected adverse events. Clinical results will be analyzed
using various statistical measures of significance.

Up to 196 subjects (multi-center) will be recruited and randomized into one of
two treatment arms.

The potential risks and benefits of participation in this study are clearly
identified in the subject informed consent form and are to be explained to the
patient prior to participation in the study.
Potential risks to the patient include the risks standard to colonoscopy
procedures including perforation, bleeding, infection, discomfort and allergic
reaction to sedation agents. All of these events could cause prolonged illness,
permanent impairment of daily function or in rare cases death. Treatment
includes, but is not limited to, abdominal surgery.
In a small percentage of cases, the colon may be perforated by a colonoscope,
causing serious risk of infection to the patient. Gatto estimated the rate of
perforation as 1.9/1000 procedures (or 0.19%) based on a large cohort of
randomly sampled Medicare patients over the age of 65 who had screening
colonoscopies, while other authors have described perforation rates above 1%.
As with any colonoscopy procedure, when using the PeerScope System* there is
some risk of bowel perforation, pain, infection, bleeding due to therapeutic
procedures such as polypectomies and inflammation. The likelihood of occurrence
of these risks is expected to be comparable to or better than conventional
colonoscopy.
The potential benefits of the PeerScope System* are identical to those of
standard colonoscopes. These benefits are: the ability to screen the entire
colon for any abnormalities that may lead to colorectal cancer; the ability to
perform therapeutic procedures such as polypectomies, when necessary. It can be
assumed that the PeerScope System leads based on the wider field of view to
higher detection rate of adenomas and thus reducing the risk for the
development of colon cancer. However, as the device is investigational, this
study is intended to validate this.