Colon Cancer 101: Symptoms, Causes, Risk Factors, Prevention, Treatment and Support Groups

by Tan Jia Hui

Medically Reviewed by M Thiviya, R.N.

Colon cancer, also known as colorectal, rectal or bowel cancer, is the most common cancer across both Singaporean males and females, with over 4,000 diagnoses in 2018.

This form of cancer occurs in the large intestine and often starts as benign lumps formed on the inner wall of the colon and rectum, called polyps. While polyps are fairly common in people above the age of 50, certain types of polyps may develop into cancer and should be removed if they are detected.

Colon Cancer Symptoms

Oftentimes, people with colon cancer may not experience any symptoms in the early stages, and when symptoms appear, they may vary depending on the size and location of the tumour.

Here are some signs and symptoms of colon cancer that you should look out for:

  • A persistent change in bowel habits, including diarrhoea, constipation and a change in stool consistency
  • Rectal bleeding or blood in the stool
  • Persistent abdominal discomfort, including gas, pain and cramps
  • Weakness or fatigue
  • Unexplained weight loss

If you notice persistent symptoms that may be of concern, consult a doctor immediately. Your doctor may then perform a colonoscopy, computed tomography (CT or CAT) scan, tumour markers or biopsy to confirm a diagnosis and determine your risk level.

Colon Cancer Risk Factors

While we are not able to determine the exact cause of colon cancer, there are several factors that may increase our risk:

Risk Factors We Cannot Control


Those above 50 years old have an increased risk of developing colon cancer. Colon cancer tends to be more common in individuals 50 years and older. However, recent studies have shown that younger individuals, too, can get colon cancer

Family History of Colon Cancer

Individuals who have family members or relatives with polyps or colon cancer are at a higher risk of developing the condition.

In rare cases, individuals may inherit a disease called familial polyposis. Those with this condition tend to develop many polyps at a young age, putting them at an extremely high risk of developing colon cancer, at 80 to 100%.

Personal History of Polyps or Colon Cancer

Those who have polyps or had been diagnosed with colon cancer previously are at a higher risk of recurrence and are encouraged to go for regular screenings.

Inflammatory Intestinal Conditions

Chronic inflammatory diseases, such as ulcerative colitis and Crohn’s disease, may increase our risk of colon cancer.

Radiation Exposure

Those who have received radiation therapy directed at the abdomen area to treat previous cancers are at a higher risk of colon cancer.

Risk Factors We Can Control

Physical Activity

Compared to their physically active counterparts, those who lead a sedentary lifestyle are at higher risk of developing colon cancer.

Studies have proven that physical activity may prevent approximately 15% of colon cancers. This is because physical activity facilitates and increases the rate of fecal passage through the intestines, allowing the potential carcinogenic substances to be excreted out of the body.


Obesity is a risk factor for colon cancer and can lead to multiple health problems. It is not just a weight issue, but a chronic, relapsing condition. High amounts of fat content increases the concentration of bile acids in the large intestine, promoting carcinogenesis.

Consider kickstarting your weight loss programme by joining a weight management programme, which can help you gain a holistic understanding of the causes of your weight gain and empower you to make positive lifestyle changes to tackle obesity sustainability.

Type 2 Diabetes

While the reasons remain unknown, it is found that individuals with type 2 diabetes are at a higher risk of developing colon cancer.

If you have diabetes, make sure to go for regular screening as early detection is key in increasing our chances of recovery. For those who do not have diabetes, learn more about how you can prevent diabetes here.


Smokers face a higher risk of developing colon cancer, a higher chance of recurrence, and are more likely to die from the condition. 

For those who do not smoke, do not start. For those who do, take the first step towards quitting today with these tips and support.


Research has shown that processed and red meat, meat cooked at high temperatures and alcohol may increase our risk of colon cancer – due to the bacterial growth from the red meat which generates carcinogens, while consumption of fruits, vegetables and dietary fibre can reduce our risk. A fibre-rich diet helps to increase the volume of stools which dilutes any carcinogenic substances in the intestines. Furthermore, dietary fibre promotes healthy and normal cell divisions in the colon.

Make sure to eat your greens to keep colon cancer at bay!

Preventing Colon Cancer

Regular screenings can help with the early detection of polyps and colon cancer. There are several tests that are used to screen for colon cancer:

Faecal Immunochemical Test (FIT)

FIT is a quick and simple test that can be carried out in the comfort of your home. It detects trace amounts of blood in faeces that are invisible to the naked eye, possibly caused by polyps or colon cancer. Usually, FIT is conducted first, followed by one of the other tests if the FIT results are positive.

It is recommended that we conduct FIT once a year. For Singaporeans or Permanent Residents aged 50 years and above, you can get your free FIT kit from Singapore Cancer Society


Colonoscopy is a procedure that involves the examination of the colon and rectum using a flexible fibre-optic instrument introduced through the anus under sedation. It may also be used for treatment, such as the removal of polyps, biopsy of cancer lumps and staunching of bleeding spots.

Individuals are recommended to undergo a colonoscopy once every 10 years to screen for polyps and cancerous growths. 

Flexible Sigmoidoscopy

Flexible sigmoidoscopy is a procedure where a short, flexible, lighted tube is inserted through the rectum to examine the internal lining of the lower end of your large intestine. 

In general, it is recommended that we undergo this procedure once every 5 years, and those at a higher risk should start screening at a younger age and/or more frequently.

Learn all you need to know about colorectal cancer screening in Singapore here.

Colon Cancer Treatment

There are various forms of treatment available for colon cancer. The effectiveness of treatment varies depending on the stage of cancer and various other factors.


The primary form of treatment for early-stage colon cancer is surgery. The aim is to completely remove cancerous sections of the colon and/or rectum, as well as its surrounding tissue and mesenteric lymph nodes. In some cases, a stoma may be created where a part of the intestine is connected to the outer surface of the skin. This provides another channel for facel matter to exit into a pouch known as a colostomy bag.The stoma may be temporary or permanent depending on the diagnosis or the operative outcome.
In some cases, laparoscopic colon surgery (also known as keyhole surgery) may be conducted instead. This minimally invasive technique is less painful and has a shorter post-operative recovery time. However, it might not be suitable for everyone. Hence, it is important to discuss with your gastroenterologist on what the best approach is.


For those with colon cancer in the more advanced stages, chemotherapy may be administered post-surgery to improve survival rates. This involves a weekly injection of drugs to kill cancer cells in the body for up to a year. 

Besides the commonly known and visible side effect of hair loss, chemotherapy can cause nausea, diarrhoea, low white cell counts and susceptibility to infection. It may also result in premature menopause and recurrence of cancer.


Radiotherapy is often conducted before and/or after surgery and involves the use of strong radioactive rays directed at specific sites of the body to destroy cancer cells. This form of treatment is administered daily, 5 days a week over 4 to 6 weeks. 

Side effects of radiotherapy are usually tolerable and temporary, and can include abdominal cramps and pain, constipation or diarrhoea, lethargy, and more.

Colon Cancer Support Groups

Coming to terms with a cancer diagnosis and undergoing treatment can be a challenging experience. Joining a support group can be beneficial for our body and minds, as individuals share support, knowledge, and tips on how to better cope with the condition.

Colorectal Support Group is one such support group that helps patients who are recovering from surgery. Through monthly meetings, members share their personal experiences, which can help us feel less alone in our fight against colon cancer. Nurses and stoma therapists are also present to provide professional advice. If you are a caring for an individual with colon cancer, there are also caregiver support groups available for you to better manage the stresses that come with caregiving.

Living with Colon Cancer

From adapting to the physical inconvenience of colostomy to dealing with the emotional effects of cancer, learning to live with colon cancer is not an easy process. However, you do not have to navigate the cancer journey alone. With the right knowledge and support, you can continue to live a fulfilling and empowered life.

If you or your loved one needs cancer care support, our trained Care Professionals can help. 

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About the Writer
Tan Jia Hui
Jia Hui is a content marketer who loves helping others and hopes to make this world a kinder place in any way she can. In her pockets of free time, you can find her snacking on ice cream and fries with her 80-year-young Grandma at home.
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