Dr Amitabh Monga
The statistics tell a chilling story of one of the top cancers in Singapore. Each year, some 1,200 people get diagnosed with colorectal cancer, which is now a leading cause of cancer-related deaths.
Yes, it may be a slow-growing cancer that usually begins as a non-cancerous polyp on the inner lining of the colon, or rectum, but if left undetected, and untreated, colorectal cancer can spread to other parts of the body, causing irreversible harm.
Being slow-growing, symptoms do not always show up in the early stages of the disease. In fact, it is often only late in the course of colorectal cancer, that patients begin to notice symptoms. As the cancer advances into its later stages, some patients may begin to notice:
While conditions such as inflammatory bowel disease, ulcerative colitis, Crohn's disease or even haemorrhoids may result in similar symptoms, these signs should never be taken lightly, especially if individuals fall within the following risk groups.
Colon cancer can affect both men and women. These are some of the usual risk factors:
Colorectal cancer has a long pre-cancerous stage where small benign polyps may grow in the lining of the colon or rectum. In most instances, they are harmless and will not develop into a cancer. However, there is a chance that some of these polyps may turn cancerous.
This is why detecting and removing them early can play a big role in preventing colorectal cancer. Colorectal cancer in its early stages is highly treatable, so screening is vital for a better outcome.
Those over the age of 50, or with a higher risk of colon cancer, should take a faecal immunochemical test (FIT) once a year. This test detects small amounts of blood in the stool that can't be seen with the naked eye. These kits are easily available in pharmacies and can be carried out in the privacy and comfort of your home.
In most cases, two fresh stool samples will need to be taken over two days and subsequently sent in for testing.
In this screening method, a patient first drinks a bowel cleansing solution at home before a CT (computerised tomography) scan on the abdomen and colon is carried out in hospital. Images of the colon are then viewed on a screen by a radiologist. While it’s an option for patients seeking a non-invasive screening method, a virtual colonoscopy will carry a significant radiation risk, and it may miss out the detection of smaller polyps. In addition, if a polyp is seen on virtual colonoscopy, a colonoscopy will be needed for polyp removal.
This is the recognised standard for colorectal screening. Undertaken as a day-procedure in hospital, the doctor will examine the lining of your colon by inserting a tube with a camera on the end (colonoscope) into the rectum and through the full length of the large intestine.
Patients will normally be sedated for the procedure, which may last between 20 – 30 minutes. If polyps are present, they will be removed by the doctor during the procedure.
The patient is required to fast and be asked to take a laxative to clear their bowels prior to the procedure. It is imperative to have an absolutely clean colon before the procedure so that the doctor will not miss any polyps.
Patients usually recover from the sedation within 30 – 60 minutes following the procedure. There is generally no pain or discomfort during or following the procedure. The doctor will then sit with the patient and explain the findings in detail.
A colonoscopy is generally a very safe procedure. Risk of any bleeding or puncture of the colon if any polyps are removed is miniscule. Bear in mind however, that one may feel a little groggy due to the sedation for a couple of hours after waking up from the sedation.
Following a colonoscopy, medical attention should be sought if:
This will be dependent on an individual's age, risk profile as well as personal and family medical history. A doctor will be best placed to advise on screening intervals. In most cases, individuals identified as being 'high-risk' may need to be screened every 2 – 3 years. For those with no history of colorectal cancer, and whose previous colonoscopy was clear, screening intervals can be far longer.
While cancer cannot be prevented with surety, the risks of developing the disease can be managed and reduced with good lifestyle habits. These include:
Should there be any doubts or questions about your risks of developing colorectal cancer, especially for those aged 50 or older, consider speaking with a gastroenterologist about a colonoscopy and how it can be included into your regular health screening routine.
Should any of the aforementioned symptoms be observed, do not delay making an appointment with a gastroenterologist for an accurate diagnosis and treatment.