Colonoscopy

A Colonoscopy is a procedure whereby a flexible instrument is inserted in the colon through the anus or back passage.

For this procedure to be effective the bowel must be clean to allow a good view of its surface. An oral preparation needs to be taken 24 hours prior to the procedure which encourages the bowel to empty its contents.

Bowel Preparations
Glycoprep AM
Glycoprep PM
Picoprep AM
Picoprep PM

The procedure is usually performed under general anaesthetic and requires a stay in hospital of only a few hours. Due to the effects of the anaesthetic, patients should avoid driving for the next 24 hours.

A colonoscopy is at present the best way in which the entire colon and rectum may be viewed and biopsies to be taken and polyps removed.

The major risk associated with a colonoscopy is perforation of the colon which, according to the National Health and Medical Research Council (NHMRC), is reported to occur in approximately one in every 600 to 1,000 colonoscopies in Australia. One of the most important factors which may influence the rate of perforation is the experience of the colonoscopist.

Perforation may be treated with or without surgery, depending on the circumstances, but if surgery is required, then on occasions it is necessary to establish a colostomy, usually as a temporary measure.

Bleeding may occur after colonoscopy but this is rarely serious and will usually stop spontaneously. Bleeding may require a repeat colonoscopy or surgery.

Both bleeding and perforation are more common if polyps are removed from the colon. It is essential to remove polyps when they are found since some may ultimately become cancerous if left.

According to the NHMRC approximately one person in 10,000 will die following a colonoscopy, usually as a result of a perforation, and usually in patients with other significant medical problems.

The above explanation is not an exhaustive list of complications. Naturally, you should consider these factors carefully before proceeding with the examination. Full details of the procedure and the risks involved will be detailed at your consultation with the doctor. Please ask any questions you feel are required for your understanding of the procedure.

Screening Colonoscopy
How often and for whom…

The recommendations below reflect the work of a number of cancer organisations and other learned bodies, as outlined in the list of sources at the end of this document, The recommendations are based on an assessment of the current state of knowledge and may vary according to the circumstances of any individual person. The members of Sydney Colorectal Associates would be happy to discuss the implications of these recommendations and how they might be relevant to your own circumstances.

One male in seventeen will develop bowel cancer in Australia, and one female in twenty-four, and there is ample evidence that screening the community, as well as high risk groups can lead to a reduction in that incidence by detecting and removing the polyps that lead to most bowel cancers.

People with

No risk factors for colorectal cancer.
Second degree relatives with colorectal cancer
First degree relatives with polyps developing when older than sixty five.
A personal history of one or two small tubular adenomas or hyperplastic or metaplastic polyps

should consider Annual faecal occult blood and five-yearly sigmoidoscopy, or ten-yearly colonoscopy from the age of fifty.

People with

A history of colorectal cancer
A first degree relative with colorectal cancer when less than sixty-five
First and second degree relatives with colorectal cancer.
Two first degree relatives with colorectal cancer on the same side of the family.
A personal history of a polyp, and a parent with colorectal cancer.
A personal history of a polyp with a villous component.
A personal history of more than two large (more than 1cm) tubular adenomas.

should consider colonoscopy every three years starting at the age of fifty, or ten years younger than the youngest age at which a relative was affected.

People with

A first degree relative greater with colorectal cancer when older than sixty five.
A first degree relative less than sixty with polyps

should consider Colonoscopy every 5 years starting at the age of fifty, or ten years younger than the youngest age at which a relative was affected.

Some groups believe that screening of patients who have relatives who develop bowel cancer under the age of sixty-five should commence at age forty.

REFERENCES

US Congress: Office of Technical Assessment: OTA-BO-H-146: April 1995. The Cost Effectiveness of Colorectal Cancer Screening in Average-Risk Adults.

National Polyp Study. Colorectal Cancer Screening: Clinical Guidelines and Rationale. S.J. Winawer et al. Gastroenterology. 1997. Volume 112. Pages 594-642.

Recommended Colorectal Cancer Surveillance Guidelines: American Society of Clinical Oncology - DESCHCE et al. J. Clinc Oncol. 1999. Volume 17. Pages 1312-1321.

American Society of Colon and Rectal Surgeons. Practice Parameters for the Detection of Colorectal Neoplasms. Diseases of the Colon and Rectum. 1999. Volume 42. Pages 1123-1129.

Guidelines for Colorectal Cancer Screening and Surveillance. American Society for Gastrointestinal Endoscopy. 2000. Volume 51. Pages 777-782.

Cost Effectiveness Analysis of Colorectal Cancer Screening: A Systematic Review for the US Preventative Services Taskforce. M. Pignone et al. Ann Intern MED 2002. Volume 137. Pages 96-104.

National Health and Medical Research Council. Clinical Practice Guidelines. The Prevention, Early Detection and Management of Colorectal Cancer. Draft. Revised 6th August, 2004.

American Cancer Society Guidelines for the Early Detection of Cancer. R.A. Smith et al. CA Cancer J Clin. 2004. Volume 54. Pages 41-52