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Colorectal Polypectomy Upon Insertion And Withdrawal Or Upon Withdrawal Only?

18 Years
Not Enrolling
Colorectal Polyps

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Trial Information

Colorectal Polypectomy Upon Insertion And Withdrawal Or Upon Withdrawal Only?

Patients with a referral for a complete colonoscopy were included in the study. Polyps were
removed upon insertion and withdrawal of the colonoscope in Group A or only upon withdrawal
of the instrument in Group B according to a computer-generated randomization list.

The following inclusion criteria were used: referral for a complete colonoscopy and age of
18 years and older. All patients with polyps detected during colonoscopy were included. In
order to compare the time required for the entire endoscopy between the two treatment
groups, we only included patients with polyps of up to 10 mm in diameter.

The following exclusion criteria were applied: colonoscopy due to bleeding, high likelihood
of colonic stenosis or severe inflammation, inflammatory bowel disease (IBD), hereditary
colonic polyp disease (FAP or HNPCC), contraindications for polypectomy, such as
coagulopathy, use of anti-clotting medication (anticoagulation, high-dose heparin aspirin,
NSAIDs), polyps >10 mm in diameter (that cannot be removed through the biopsy channel and
have to be removed by basket or polyp grasper; the use of these devices necessitates removal
and consecutive re-insertion of the endoscope, making a comparison of the time intervals
between the two groups impossible), suboptimal bowel preparation (presence of significant
amounts of fecal remnants that could not be removed by flushing of the colon over the
colonoscope and that did not allow clear visualization of the mucosa), and missing signed
informed consent form.

The randomization was done as soon as the first polyp was detected. When no polyps were
detected, the case was regarded as screening failure and excluded from the study.

Randomization was performed into the following two groups:

Group A: Removal of all visible polyps upon insertion and withdrawal of the instrument Group
B: Removal of all visible polyps upon withdrawal of the colonoscope only One day after
colonoscopy, patients were asked to complete a questionnaire evaluating the tolerance of the
ileo-colonoscopy (on a visual scale from 1 to 4 where 1 stands for no discomfort, 2 for
minor discomfort, 3 for moderate discomfort, and 4 for severe discomfort associated with the

Endoscopic procedures:

Colon preparation was performed using 3 liters of PEG-based standard lavage fluids (Fordtran
Streuli ®, Streuli Pharma, Switzerland).

The procedures were performed by senior endoscopists (SW, SRV, HF, NW, PB) with at least 5
years of experience in colonoscopy and performing at least 200 colonoscopies per year. All
endoscopists participating in this trial underwent a specific study training headed by SW.
Polyp size was measured using an opened biopsy forceps (Boston Scientific Radial JawTM 4,
Reference No 1332, diameter of opened jaws 9mm). All endoscopists had comparable numbers of
procedures in both approaches to polypectomy.

Premedication consisted mostly of propofol (60-400 mg) or a combination of midazolam (2.5-5
mg) and/or meperidine (25-50 mg) intravenously. Examinations were performed in left lateral
decubitus or supine position. Colonic insufflation was performed with room air. All
polypectomies in the study groups were performed using the same techniques as in the
standard care of non-study patients, using snare loops, hot biopsy forceps, with and without
submucosal injection of saline/epinephrine. Polyps larger than 3 mm were removed by snare,
polyps smaller than 4 mm were removed by cold biopsy. There were no differences upon
insertion or withdrawal.

In Group A, the endoscopist removed all visible polyps instantly regardless whether
advancing the instrument to the cecum or pulling back. In Group B, the endoscopist advanced
the endoscope to the cecum without removing polyps. Upon withdrawal, all visible polyps were
removed successively by standard techniques. In both groups, the endoscopists were
instructed to focus on rapid introduction.

Assessments After the endoscopy, the physician completed the data capture sheet evaluating
the following criteria: patient demographics, patient history, time intervals required for
the procedure, number of polyps detected upon insertion, number of polyps removed upon
insertion, number of polyps removed upon withdrawal, overall technical ease (score from 1 to
4 where 1 stands for no technical problems, 2 for minor, 3 for moderate, and 4 for major
technical difficulties), presence of technical problems (difficult visualization of the
polyps, difficult removal of polyps, and difficult retrieval of polyps, all answered
categorically with "Yes" or "No"), patient tolerance (completed by patients), and
characterization of every polyp (location, size, time of removal and additional comments).

Inclusion Criteria:

- Need for a complete colonoscopy

- 18 years of age and older

Exclusion Criteria:

- Need for urgent colonoscopy due to bleeding

- High likelihood of colonic stenosis or severe inflammation

- Known inflammatory bowel disease (IBD)

- Known familiarity adenomatous polyposis (FAP)

- Contraindications for polypectomy such as coagulopathy, use of anti-clotting
medication (anticoagulation, aspirin, NSAIDs)

- Missing signed consent

Type of Study:


Study Design:

Allocation: Randomized, Intervention Model: Parallel Assignment, Masking: Double Blind (Subject, Outcomes Assessor), Primary Purpose: Prevention

Outcome Measure:

Polyp detection

Outcome Time Frame:

2004 - 2007

Safety Issue:


Principal Investigator

Stephan M. Wildi, MD

Investigator Role:

Principal Investigator

Investigator Affiliation:

University of Zurich


Switzerland: Ethikkommission

Study ID:




Start Date:

April 2004

Completion Date:

April 2007

Related Keywords:

  • Colorectal Polyps
  • polypectomy
  • colonoscopy
  • polyp miss rate
  • surveillance
  • colorectal cancer
  • Polyps
  • Colonic Polyps