Your comprehensive guide to colorectal cancer (cancer of the colon and/or rectum) — the most common cancer in Singapore.
Did you know that the earlier you detect colorectal cancer, the more curable it is?
From its risk factors to diagnosis and cancer treatment options, get the facts on colorectal cancer — the most commonly diagnosed cancer in Singapore, but also one of the most treatable if detected at an early stage.
Colorectal cancer refers to both colon cancer or bowel cancer. The colon is the main part of the large intestine, while the rectum is the passageway connecting the colon and anus. Cancer of the colon and cancer of the rectum are grouped together as colorectal cancer because they share common features. Colorectal cancer usually develops from polyps, which are growths on the inner walls of the colon and rectum. Commonly found in people age 45 and above, polyps may become cancerous after 10 to 15 years. As such, they should be removed upon detection.
According to the Singapore Cancer Registry Annual Report 2015, some 35 people are diagnosed with cancer every day in Singapore — with colorectal cancer being the most common diagnosis. A total of 9,807 new cases were diagnosed between 2011 and 2015.
Colorectal cancer is the most common type of cancer among men, and the second-most commonly diagnosed cancer among women after breast cancer. In Singapore, approximately one in six men and one in seven women diagnosed with cancer between 2011 and 2015 had colorectal cancer.
Colorectal cancer is one of the most preventable and treatable cancers if you are screened regularly. At an early stage, colorectal cancer cells are confined to the large intestine and, if detected and removed, may greatly reduce your risk of cancer development.
Cancer treatment is also most effective in the early stages of colorectal cancer. The survival rates for men and women are around 84 percent and 86 percent respectively, if the cancer is detected at stage one. However, survival rates drop steeply to just 10 percent for men and 11 percent for women if the cancer reaches stage four.
If you have a personal or family history of colorectal cancer or polyps in the colon, you may be at a higher risk of developing colorectal cancer. Your chance of developing colorectal cancer also increases if you suffer from inflammatory bowel disease, such as ulcerative colitis and Crohn’s disease. According to SingHealth, Singapore’s largest healthcare group, most people diagnosed with colorectal cancer are older than 45 years old.
Regular health screenings are important in helping to diagnose and prevent colorectal cancer. Several types of screenings are available, depending on your individual risk factors. Please discuss colorectal cancer screening with your doctor.
The Faecal Immunochemical Test (FIT) is a simple and convenient test that can be done in the comfort of your home. It detects the presence of small amounts of blood in stools that may be invisible to the naked eye. The test is safe and should be conducted once a year
· A colonoscopy involves the examination of the colon and rectum using a flexible fibre-optic instrument that is inserted into the anus under sedation. This procedure is carried out by a specialist at a clinic and is recommended to be done once every 10 years
· A flexible sigmoidoscopy examines the internal lining of the lower end of the large intestine. A short and flexible tube is inserted into the rectum and slowly guided into the sigmoid colon, which is the last part of the colon leading into the rectum. This exam is recommended to be done once every five years.
Certain food, such as processed meat, red meat, meat cooked at high temperatures and animal fat, have been found to increase the risk of colorectal cancer. To lower your chances of developing colorectal cancer, eat less of such food and increase your fibre intake. You may also avoid smoking and excessive alcohol, and maintain a healthy lifestyle by staying active, exercising regularly and keeping a healthy weight.
At an early stage, colorectal cancer often presents no cancer symptoms. In many cases, it tends to be diagnosed at the later stages. According to the Singapore Cancer Registry Annual Report 2015, about one-third of cases in Singapore are diagnosed at stage three and a quarter at stage four — for both males and females.
Although there are usually few or no symptoms for colorectal cancer at the early stages, you should still lookout for the following:
To determine the stage of the cancer, doctors have to examine how deeply the cancer cells have invaded the intestinal walls and if they have spread to adjacent lymph nodes and other organs. Then, depending on the cancer stage, doctors will offer various cancer treatment options.
Surgery removes the tumour in the intestine and the surrounding lymph glands affected by the cancer. Most of the time, the two ends of the colon must be sewn together to restore the functions of the colon and rectum. Some patients may require a stomach bag. However, the need for colostomies may reduce increasingly as surgical techniques continue to improve. Newer surgical methods like laparoscopic and keyhole surgery help patients to reduce recovery time, minimise infection and avoid long scars after surgery.
Radiotherapy is the next step after surgery to kill any residual cancer cells around the original tumour site. When combined with chemotherapy, it can be used to shrink the size of the colorectal cancer before surgery. However, it is more often conducted after surgery to remove any remaining cancer cells and prevent the cancer from recurring.
Chemotherapy, which administers anti-cancer drugs to the patient, is used when the cancer has spread to other organs such as the liver or lung. It is also performed on selected patients after surgery to lower the chances of the cancer recurring.
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This article was last reviewed on 17 Jan 2023
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