COLONOSCOPY SCREENING SINGAPORE
What is colonoscopy?
In Singapore Colonoscopy is the best procedure that enables the doctor to evaluate the inside of the colon (large intestine or large bowel). The colonoscope is a four-foot-long, flexible tube about the thickness of a finger with a camera and a source of light at its tip. The tip of the colonoscope is inserted into the anus and then is advanced slowly, under visual control, into the rectum and through the colon usually as far as the cecum, which is the first part of the colon. Usually, it also is possible to enter and examine the last few inches of the small intestine (terminal ileum
Why is colonoscopy done?
Colonoscopy may be done for a variety of reasons. The vast majority of colonoscopies are performed as part of screening programs to diagnose colon cancer. When done for other reasons, it is most often done to investigate the cause of blood in the stool, abdominal pain, diarrhea, a change in bowel habit or an abnormality found on colonic X-rays or computerised axial tomography (CT) scan.
Individuals with a previous history of polyps or colon cancer and certain individuals with a family history of some types of non-colonic cancers or colonic problems that may be associated with colon cancer (such as colonic polyps) may be advised to have periodic colonoscopies because their risks are greater for polyps or colon cancer.
What bowel preparation is needed for colonoscopy?
If the procedure is to be complete and accurate, the colon must be completely cleaned and there are several different colonoscopy preparations. Patients are given detailed instructions about the cleansing preparation. In general, this consists of drinking a large volume of a special cleansing solution a day before examination and laxatives or enemas prior to the examination. These instructions should be followed exactly as prescribed or the procedure may be unsatisfactory (visualisation of the lining of the colon may be obscured by residual stool) and it may have to be repeated or a less accurate alternative test must be performed in its place.
Instructions may also be given to avoid certain foods for a couple of days prior to the procedure, such as stringy foods, high fibre foods or foods with seeds.
Can I take my medications before a colonoscopy? Is there a special diet?
Most medications should be continued as usual, but some may interfere with the examination. It is best if the colonoscopist is informed of all current prescription and over-the-counter medications. Aspirin products, blood thinners such as warfarin (Coumadin), arthritis medications, insulin and iron preparations are examples of medications that may require special instructions. The colonoscopist will also want to be aware of a patient’s allergies and any other major illnesses. The colonoscopist should be alerted if, in the past, patients have required antibiotics prior to surgical or dental procedures to prevent infections.
What should I expect during colonoscopy?
Prior to colonoscopy, intravenous fluids are started, and the patient is placed on a monitor for continuous monitoring of heart rhythm and blood pressure as well as oxygen in the blood. Medications (sedatives) usually are given through an intravenous line so the patient becomes sleepy and relaxed and to reduce pain. If needed, the patient may receive additional doses of medication during the procedure. Colonoscopy often produces a feeling of pressure, cramping, and bloating in the abdomen; however, with the aid of medications, it is generally well-tolerated and infrequently causes severe pain.
What If there are abnormalities detected during colonoscopy?
If an abnormal area needs to be better evaluated, a biopsy forceps can be passed through a channel in the colonoscope and a biopsy (a sample of the tissue) can be obtained. The biopsy is submitted to the pathology laboratory for examination under a microscope by a pathologist. If infection is suspected, a biopsy may be obtained for culturing of bacteria (and occasionally viruses or fungus) or examination under the microscope for parasites. If colonoscopy is performed because of bleeding, the site of bleeding can be identified, samples of tissue obtained (if necessary), and the bleeding controlled by several means. Should there be polyps, (benign growths that can become cancerous) they almost always can be removed through the colonoscope. Removal of these polyps is an important method of preventing colon and rectal cancer, although the great majority of polyps are benign and do not become cancerous. None of these additional procedures typically produces pain. Biopsies are taken for many reasons and do not necessarily mean that cancer is suspected.
What should I expect when my Colonoscopy is done?
Patients will be kept in an observation area for an hour or two post-colonoscopy until the effects of medications that have been given wear off. If patients have been given sedatives before or during colonoscopy, they may not drive, even if they feel alert. Someone else must drive them home since their reflexes and judgment may be impaired for the rest of the day, making it unsafe to drive, operate machinery or make important decisions. Should patients have some cramping or bloating, this can be relieved quickly with the passage of gas and they should be able to eat upon returning home. After the removal of polyps or certain other manipulations, the diet or activities of patients may be restricted for a brief period of time.
What are the possible risks, complications, or alternatives to colonoscopy?
Complications of colonoscopy are rare and usually minor when performed by physicians who have been specially trained and are experienced in colonoscopy.
What is virtual colonoscopy?
Virtual colonoscopy has difficulty identifying small polyps (less than 5 mm in size) that are easily seen at colonoscopy though it is true that small polyps are less likely to be cancerous.
Virtual colonoscopy has great difficulty identifying flat cancers or premalignant lesions that are not protruding, that is, are not polyp-like.
Virtual colonoscopy does not allow removal of polyps that are found. Thirty to forty percent of people have colon polyps. If polyps are found by virtual colonoscopy, then colonoscopy must be done to remove the polyps. Therefore, many individuals having virtual colonoscopy will have to undergo a second procedure, colonoscopy.
Virtual colonoscopy exposes individuals to a moderate amount of radiation.
Virtual colonoscopy does not allow the use of the newer techniques that are being developed to differentiate between abnormal lesions that need to be biopsied or removed and those that don’t.