Colorectal cancer is one of the most common cancers worldwide.
Fortunately, it is also one of the most preventable cancers with the help of screening. Colorectal cancer develops from polyps, but polyps do not have symptoms. However, the removal of polyps (polypectomy) in turn prevents it from developing further into colorectal cancer. This is how screening via Colonoscopy helps prevent colon cancer.
Early-stage curable colorectal cancer has virtually no symptoms, but screening via Colonoscopy again helps with the early detection of colorectal cancer. Early-stage colorectal cancer has a 5-year survival rate of 80-90%, and early detection is key.
A colonoscopy is routinely offered to adults above the age of 50 for screening for polyps and also early detection of colorectal cancer. Those with the following risk factors are at higher risk for colorectal cancer and should consider earlier screening:
- A family history of colorectal cancer
- Genetic syndromes like familial adenomatosis polyposis or HNPCC
- A personal or family history of inflammatory bowel diseases
- Being overweight
- Having Type 2 diabetes
- Consuming a high-fat diet
- Drinking alcohol regularly
- Not exercising regularly
Your doctor may also recommend a colonoscopy if you show symptoms suggestive of cancer, such as blood in your stools or unexplained abdominal pain or changes in your bowel movement habits.
Colorectal cancer is the most common cancer in males in Singapore and the second most common for females in Singapore, making routine colonoscopies important.
Before going for a colonoscopy, you are recommended to arrange for a day of leave on the day of the scope.
Bowel preparation is important in the days leading up to the colonoscopy.
The type of food you should avoid include:
- Nuts and seeds
- Juices with fruit pulp
- High fibre food
- All vegetables
- Brown rice and wholemeal bread
- Cereals and oats
You are only required to abstain from food about 6-8 hours before the scope. You can continue to drink water until 2hrs before your scope.
You will also be prescribed bowel clearance medications that will bring you to the toilet about 7-10 times to clear your colon.
Before the procedure, most patients are put under IV sedation to ensure a comfortable procedure. You will be unaware of the proceedings during the scope. You will then be positioned to the side, with your knees curled towards your torso.
A long, flexible and thin tube with a miniature camera and attached light (colonoscope) will be inserted into the rectum via the anus. This allows your doctor to visualise the gastrointestinal tract for any polyps, tumours, vascular malformations or any other structural abnormalities that line your gut.
Polyps can be removed (polypectomy) via instruments inserted through the colonoscope by snipping off the tissues or burning them with electrocautery. Similarly, if your doctor detects any abnormalities, they can obtain a biopsy for further examination, if needed. These procedures do not cause any pain both during and after the procedure.