The aim of this study is to compare the colonoscopy success rate, cecal time and polyp detection rate between cap-fitted colonoscopy and conventional colonoscopy.

Colonoscopic examination has been used in clinical practice for approximately 40 years. Despite the fact that colonoscopy is widely available and is performed by many experienced colonoscopists there are concerns about the quality of colonoscopy as measured by several technical endpoints such as rate of failed caecal intubation and polyp miss rate. A large population-based study revealed 13.1% of colonoscopies failed to reach the cecum. In addition, one large review of back-to-back colonoscopies showed polyp miss rates of 24% for adenoma.

One potentially promising technique is cap-assisted colonoscopy. A transparent cap (or "hood") is a simple plastic device that can be attached to the tip of a colonoscope before performing the colonoscopy. Several randomized trials from Japan have mixed results regarding improved cecal intubation times and polyp detection rates. A recent large study from Hong Kong showed improved time to cecum but a reduced polyp detection rate. To date there is no large randomized study using the cap in a western population, in whom the colorectal cancer (CRC) incidence is known to be higher. We plan to conduct a randomized controlled trial to investigate the usefulness of cap-assisted colonoscopy in a Western population.

Inclusion Criteria:

• All colonoscopy patients referred for colonoscopy at Royal Prince Alfred Hospital.

Exclusion Criteria:

• Prior colonic resection
• Pregnancy.
• Severe co-morbidities.
• Tertiary referral for endo-mucosal resection.
• Acute surgical conditions such as severe colitis, toxic megacolon, ischemic colitis, acute gastrointestinal bleeding.