Colorectal cancer, also known as colon cancer, is cancer occurring in the longest part of the large intestine or rectal area. Colorectal cancers usually begin in cells on the inner wall of the colon or rectum that produce mucus and other fluids, forming abnormal growths called polyps. Most of the time, polyps tend to be harmless, however, some of these polyps may turn into malignant tumours that cause cancer.
Through the years, the number of colorectal cases has been increasing in both males and females. Colorectal cancer is the most common cancer affecting males in Singapore, having one of the highest numbers in Asia compared to counterparts like Taiwan and Japan. Unlike other cancers, colorectal cancer has a much higher rate of successful treatment if detected at earlier stages.
Here are 6 facts you need to know about colorectal cancer, such as its prevalence, symptoms, risk factors, treatment options, as well as how a colonoscopy is important in early detection and treatment.
6 facts about Colorectal Cancer in Singapore
1. WHY DO I NEED TO KNOW ABOUT COLORECTAL CANCER?
Colorectal cancer is cancer that occurs in the colon (large intestine) or rectum. It mainly affects people above the age of 50.
According to the Singapore Cancer Registry, about 1,500 patients are diagnosed with colorectal cancer annually. About 650 patients die from it each year.
In Singapore, colorectal cancer is the:
• No. 1 most common cancer in men (about 1 in 6 of male cancer patients)
• No. 2 leading cause of cancer deaths in men
• No. 2 most common cancer in women (about 1 in 7 of female cancer patients)
• No. 3 leading cause of cancer deaths in women
Hence when both male and female cancers are combined, it is the most common cancer.
2. WHAT CAUSES COLORECTAL CANCER AND WHO ARE AT RISKS?
In most cases, colorectal cancer begins as benign polyps on the inner wall of the colon or rectum that develop into malignant tumours over a period of five to 10 years. The risk of developing colorectal cancer increases if you:
• Have a family history of colorectal cancer
• Are above 50 years old
• Have polyps in your colon or rectum (most are benign but some can develop into cancer)
• Bad lifestyle. (Smoke, or consume a diet that is high in fat, red meat, processed meats and low in fruits and vegetables.)
3. WHAT ARE THE SYMPTOMS?
Although more than half the people diagnosed with colorectal cancer have no symptoms, here are some signs to look out for:
• Change in bowel habits (diarrhoea or constipation)
• Blood in your stools
• Persistent abdominal pain
• Feeling of bowel not emptied completely (Tenesmus)
• Constantly feeling full or bloated
• Unexplained weight loss
• Having nausea or vomiting
These symptoms are not specific to cancer and could be caused by other health problems. But if you have these symptoms, do see a doctor to be diagnosed and treated as early as possible.
4. CAN COLORECTAL CANCER BE PREVENTED?
Colorectal cancer is entirely preventable via regular colorectal cancer screening. It is of the most powerful weapons for preventing colorectal cancer. Precancerous polyps can be present, often without symptoms, in the colon for years before invasive cancer develops. Colonoscopy can find precancerous polyps so they can be removed before they turn into cancer. In this way, colorectal cancer is prevented.
If you are 50 years old or older, you should go for:
• Faecal Immunochemical Test (FIT) once every year — for detection of hidden blood in the stool. (Diagnostic test only)
• Colonoscopy once every 10 years — for examination of the colon and rectum via a long, lighted tube (colonoscope). This is the Gold standard screening test as it is both diagnostic and therapeutic.
If you have a family or personal history of colorectal cancer, you should:
• Start screening at 50, or 10 years before the youngest family member had colorectal cancer, whichever is earlier.
• Get a colonoscopy done every one to three years.
5. WHAT ARE THE TREATMENT OPTIONS?
An important step following the diagnosis of colorectal cancer is to determine its stage.
Cancer stage refers to the spread of a cancer in the body. The staging of colorectal cancer is based on the size of the tumour, whether lymph nodes are involved and whether the cancer has spread to other parts of the body (such as the liver and lungs).
Stage 1 represents the earliest stage of cancer while Stage IV represents the most advanced stage, where the cancer has spread to other parts of the body. Different types of treatment are available for patients with colorectal cancer. Broadly, these treatments are:
• Surgery
• Chemotherapy
• Radiotherapy
• Immunotherapy
The type of treatment recommended will depend on several factors, including the cancer stage and overall health of the patient. In general, Stage 1 and 2 requires surgery only. Stage 3 and 4 often require surgery in combination with chemotherapy and/or radiotherapy/immunotherapy.
6. HOW DO I LOWER MY RISKS OF COLORECTAL CANCER?
Early detection of precancerous colorectal polyps via timely colorectal screening.
The Gold standard for screening is colonoscopy which is both diagnostic (detects polyps) and therapeutic (removes the polyps before it progresses to cancer).