Approximately 5 Singaporeans are diagnosed with colorectal cancer every day. It is one of the 3 leading cancers in Singapore, regardless of gender and ethnicity. It is more common in men than in women, but harder to diagnose in women because it may be wrongly attributed to menstruation or other gynaecological problems. Read more about colorectal cancer in women here.
So, what is colorectal cancer and why is it so prevalent in Singapore? What can we do about it and when should we seek help? We’re here to let you in on all the details about colorectal cancer.
What is colorectal cancer?
Colorectal cancer is better known as colon cancer, rectal cancer or bowel cancer. It is the cancer of the colon, which is the longest part of the large intestine, or rectum, the part of the large intestine just before the anus.
Why is colorectal cancer so prevalent in Singapore?
In Singapore, more people are becoming obese due to our lack of exercise and poor dietary habits. The fact is that those who are overweight, smoke, drink a lot or consume a high-fat diet are at higher risk of developing colorectal cancer. Diabetes is also on the rise in Singapore and those with type 2 diabetes are also more likely to develop colorectal cancer.
What are the risk factors for colorectal cancer?
Colorectal polyps are benign growths on the inner wall of the colon or rectum. These are usually harmless but could turn cancerous.
Ulcerative colitis or Crohn’s Disease
Ulcerative colitis or Crohn’s disease are collectively known as inflammatory bowel disease (IBD), and both involve inflammation of the colon. They cause swelling of the colon and can increase the chances of you developing colorectal cancer.
Personal history of cancer
If you have had colorectal cancer before, you are more likely to develop it again. Women with a history of cancer in the ovaries, uterus, or breasts are also at higher risk of colorectal cancer.
Family history of colorectal cancer
If you have family members who have had colorectal cancer before, especially at a young age, you are at higher risk of getting it too.
Lifestyle factors like smoking, drinking or poor diet
Smoking, drinking or eating a diet high in fat and low in fibre may increase your chances of developing colorectal cancer. Obesity also makes colorectal cancer more likely.
Those above the age of 50 are more likely to get colorectal cancer. 90% of colorectal cancer patients are over the age of 50.
What are the signs and symptoms of colorectal cancer?
- Changes in bowel habits such as diarrhoea or constipation
- A feeling that you have not completely emptied your bowels
- Blood in the stool which can be bright red or dark red
- Bloating and pain or cramps
- Unexplained weight loss
- Chronic fatigue
- Nausea or vomiting
These symptoms may also be caused by other health problems unrelated to cancer, so if you have them, do seek help early from doctors. Another important thing to note is that early-stage cancer may not present with these symptoms, or the symptoms may not be that obvious yet. Get screened for colorectal cancer if you have these symptoms.
When should I see a doctor for colorectal cancer?
See your doctor if the common signs and symptoms for colorectal cancer persist for over 2 weeks and are affecting your daily life.
How is colorectal cancer diagnosed?
Screening tests can help your doctor to find polyps or cancerous growths before symptoms show up. Early detection of colorectal cancer greatly improves the success rate of treatment. The following screening tests may be done to detect polyps or cancers or other abnormalities of the colon and rectum.
Faecal Occult Blood Test (FOBT)
This test is used to detect blood in stools because cancer or polyps may cause bleeding in the intestines. If there is blood in the stool, other tests may be done to find the source of the bleeding. Colorectal cancer isn’t the only condition that causes bleeding – other benign conditions like haemorrhoids could do the same.
The rectum and lower part of the colon can be examined and viewed with a sigmoidoscope tube to look for polyps which can then be removed.
Colonoscopy involves using a long tube with a camera or colonoscope to examine the inside of the intestines and colon. The polyps found may be removed during the colonoscopy.
Double-contrast Barium Enema
This involves filling the colon and rectum with a silver-white metallic liquid called barium which helps improve the X-rays, allowing polyps or other abnormalities to show up on the scans.
Virtual Colonoscopy (CT Colonography)
Pictures of the colon and rectum are taken with specialised X-ray equipment using low dose computed tomography (CT). The computer software then combines these images to produce 2D and 3D views of the interior of the intestines and colon. This procedure is sometimes called CT colonography.
What are the treatment options for colorectal cancer?
Surgery (Early stages)
If the cancer is small, localised and contained inside a polyp and in its early stages, the doctor may remove it via a type of colonoscopy called a polypectomy.
- Endoscopic mucosal resection
For larger polyps, they may be removed during colonoscopy using specialised tools that also remove a small part of the mucosal lining of the colon along with the polyp,
- Laparoscopic surgery
If your polyp cannot be removed through colonoscopy, the doctor might suggest laparoscopic surgery instead. It is a minimally invasive surgery where your surgeon will make several small incisions in your abdomen.
Surgery (More advanced stages)
- Partial colectomy
In this surgery, part of the colon is removed along with the cancerous growth. The surgeon then reconnects the healthy parts of the colon or rectum. This can be done using laparoscopy.
An ostomy is a surgery for waste to leave your body through an opening in the abdomen. It is needed when it is not possible to reconnect the healthy parts of the colon.
- Lymph node removal
Lymph nodes may also be removed during colon cancer surgery to be tested for cancer.
This is the use of anti-cancer drugs to destroy cancer cells and they may be taken orally or through injections. These drugs travel in the bloodstream to reach different parts of the body.
Targeted cancer therapy
Targeted cancer therapy is a cancer treatment that uses drugs affecting specific molecules involved in cancer growth, thus halting the spread of cancer.
Radiation or radiotherapy involves the use of high doses of radiation to destroy cancer cells in an area of the body.
How can I prevent colorectal cancer?
There are some ways to prevent colorectal cancer, although some factors like age are not within our control.
Have a balanced diet
Cut down on processed meat like bacon, sausages and ham, as well as red meat like beef, lamb and pork because they increase the risk of developing cancer. Instead, incorporate fruits, vegetables and high-fibre foods into your diet to help you maintain a healthy weight and reduce the risk of obesity and diabetes. Here are some foods you may wish to take to actively prevent colorectal cancer.
Reduce alcohol consumption
Alcohol turns into acetaldehyde when in the body, a toxic chemical which can damage DNA and prevent the body from repairing the damage. It also triggers high cell growth which may lead to more mutations that lead to cancer. Therefore, avoid alcohol if you wish to avoid cancer.
Staying active will help your body to digest food faster, which means cancer-causing chemicals are flushed out of your body quicker. It also reduces inflammation of the intestines, keeping the body healthy.
Do not smoke
Those who smoke are at higher risk of developing and dying from colorectal cancer.
Colorectal cancer is a serious problem, but the good news is that it can be treated and managed with early diagnosis. It is recommended that you go for regular screenings from age 45 onwards to find and remove precancerous growths or polyps in the colon and rectum, which can help you to prevent cancer. Talk to your doctors to find out more about whether you should start screening, and which tests you should be taking.
If you or your loved one is suffering from colorectal cancer, here are some ways to cope.
Meanwhile, keep active and eat a balanced diet to keep obesity and diabetes at bay, and don’t drink or smoke. These will help to reduce the risk of cancer and help keep you healthy and happy for a long time to come.
- Kuipers, E. J., Grady, W. M., Lieberman, D., Seufferlein, T., Sung, J. J., Boelens, P. G., van de Velde, C. J., & Watanabe, T. (2015). Colorectal cancer. Nature reviews. Disease primers, 1, 15065. https://doi.org/10.1038/nrdp.2015.65
- Marley, A. R., & Nan, H. (2016). Epidemiology of colorectal cancer. International journal of molecular epidemiology and genetics, 7(3), 105–114.
- Chapelle, N., Martel, M., Toes-Zoutendijk, E., Barkun, A. N., & Bardou, M. (2020). Recent advances in clinical practice: colorectal cancer chemoprevention in the average-risk population. Gut, 69(12), 2244-2255.
This article was written and medically reviewed by Dr. Ganesh Ramalingam, M.D.