Trial Information

Colorectal cancer (CRC) is the leading cause of cancer death not only in the Western
countries but also in Taiwan. It is now the third leading cause of cancer mortality both in
men and women in Taiwan. Previous studies revealed early detection of adenomatous polyp, the
precursor lesion of CRC, plays a pivotal role in CRC prevention and removal of these lesions
was proven to reduce CRC mortality. Fecal occult blood test (FOBT) is now the standard mass
screening modality and colonoscopy is the standard procedure of choice if FOBT was positive.
Nevertheless, colonoscopy is now gradually accepted as one of the powerful tool for
colorectal cancer screening. Not only for survey after positive fecal test, it is also
applied as primary screening modality for CRC screening.Colon cleansing before colonoscopy
thus becomes critically important and inadequate preparation may lead to low diagnostic
yield with missed lesions, increased risk of complication and prolonged procedure time.
Though the importance of good colon preparation can not be over-emphasized, diet control
before colonoscopy and ingestion of large amount of lavage solution remain a significant
hurdle to overcome and investigators continue to seek for the ideal colon preparation with
respect to quality and examinee satisfaction.

After the introduction of polyethylene glycol electrolyte lavage solution (PEG-ELS) for
bowel preparation before colon procedures, its safety was well documented and the efficacy
of colon cleansing was proven efficient. The timing of ingesting PEG-ELS is different
between institutes and some ingest PEG-ELS as a whole at the night before colonoscopic
examination and some ingested in split-dose manner which ingest half of the solution at
previous night and remaining on the day of examination. Some institutes ask examinee to
receive lavage solution on the day of examination. The manufacturer advices start taking
medication on the day before the investigation according to their printed instruction on the
package of PEG-ELS. Though there were a lot of studies that conducted to describe the result
of colon cleansing in different fashion, the result is still controversial.

This prospective, randomized, single-blinded trail evaluated and compared the efficacy of
colon preparation at two timing of colon preparation, namely, in previous night or on the
day of colonoscopic examination. In this study, we enrolled those who have already colon
neoplasia detected during voluntary routine health check-up and received second colonoscopic
examination for either elective polypectomy or endoscopic mucosectomy (EMR). We used not
only the cleansing condition as a reference of adequate preparation; we also compared the
diagnostic yield of lesion number as an objective comparator between these two methods.