Bowel Cancer Screening Program
Bowel cancer screening involves techniques to look for early cancer of the colon or rectum. Bowel cancer is a common type of cancer in both men and women. About 1 in 20 people will get it during their lifetime. Screening can help detect bowel cancer at an early stage, when it’s easier to treat. More important that detecting early cancer, bowel cancer screening actually aims to check for small growths in the colon called polyps which can turn into cancer over time. These colon polyps can be easily removed thus preventing the formation of cancer at a later date.
Types of screening test:
There are several types of test used for bowel cancer screening:
Colonoscopy: The most reliable test to detect early cancers and polyps in the colon or rectum is a colonoscopy. This is an endoscopic examination in which a thin, flexible tube with a camera at the end is inserted into an individual’s colon for a complete examination. If any polyps are found, they can be removed at the same time by an easy procedure known as polypectomy. Colonoscopy requires bowel cleansing which has to be done a day prior to the procedure. For this, the individual has to drink a special powder mixed with a couple of liters of water. Colonoscopy is done under intravenous sedation and generally it does not cause discomfort. The actual procedure of colonoscopy takes about 15 to 20 minutes, but one may have to stay at the hospital for up to 4 hours to completely recover from effects of sedative medications. It is recommended that one has a colonoscopy once every 10 years after the age of 45.
Sigmoidoscopy: This is shorter form of colonoscopy using a similar thin flexible tube with a camera. During sigmoidoscopy, only the rectum and the left side of the colon (up to 60 cm) is examined. Bowel cleansing is not required (except for an enema to evacuate the bowel just prior to the procedure), and it can be done without sedation. This makes the whole procedure simpler and faster. The aim is to look at the rectum and left side of the colon where most (80%) of the cancers usually occur. In case polyps are found in the left colon, it is then recommended that a full-length colonoscopy be done to look for polyps in the remainder of the colon. In case an individual opts for sigmoidoscopy instead of a colonoscopy for bowel cancer screening, then one should do this procedure once in 5 years after the age of 45.
CT colonography or Virtual colonoscopy: This is a technique which has been developed to detect polyps in the colon without actually inserting a tube in the colon. Bowel cleansing is required. During the procedure, the individual lies under a CT scanner and air is inflated in to the colon, following which CT scan images are taken and reconstructed using special software to give a virtual view of the interior of the colon. If polyps are suspected on these virtual views, the individual can then undergo a colonoscopy on the same day to remove these polyps.
Stool test: The stool test essential detects tiny amounts of blood that an individual with a colon polyp or early colon cancer may be passing in his stools. It is important to understand that small polyps may not cause any bleeding and therefore this test is not very accurate but in case a person is not willing to get a colonoscopy done, it is recommended that this test be done once every year. If the stool test does come back as positive for blood in the stool, then a colonoscopy is mandatory.
Who should do bowel cancer screening?
It is recommended that people over the age of 45 or over should strongly consider getting screened for bowel cancer. Some individuals who fall into one of the following categories may need more frequent screening starting at a younger age.
- A strong family history of colon or rectal cancer or certain types of polyps
- A personal history of colorectal cancer or certain types of polyps
- A personal history of inflammatory bowel disease (ulcerative colitis or Crohn’s disease)
- A known family history of a hereditary colorectal cancer syndrome such as familial adenomatous polyposis (FAP) or Lynch syndrome