Colon Cancer: Causes and Risks

Colorectal cancer is one of the leading types of cancer in first world countries. It’s no different in Singapore, where it ranks in the top three number of new cancer cases for both males and females of all ages.

Colon cancer is a type of cancer that begins in the large intestine, or what’s commonly known as the colon. Although colon cancer typically affects older adults, it can happen at any age. It usually begins as small, noncancerous (benign) clumps of cells called polyps that form on the inside of the colon. Over time some of these polyps can become colon cancers.

There are different screening tests readily available, including the Faecal Immunochemical Test (FIT), Colonoscopy, and Flexible Sigmoidoscopy. Therefore, it’s important to get screened regularly so that any abnormalities can be discovered at an earlier stage.

Colon Cancer Causes And Risks

Risk Factors

While doctors are not certain what exactly causes most colon cancers, risk factors include:

Family History

You’re more likely to develop colon cancer if you have a relative who has had the disease. If more than one family member has colon cancer or rectal cancer, your risk is even greater. Certain inherited gene mutations can also increase your risk of colon cancer significantly, including familial adenomatous polyposis (FAP) and Lynch syndrome.


Some studies have found an increased risk of colon cancer in people who eat diets high in red meat and processed meat such as roast beef, jerky, ham and hot dogs. The same goes for meats prepared at high temperatures – think grilling, pan-frying. Although there are conflicting studies, in general, one may reduce their cancer risk by maintain a healthy diet through higher consumption of fruits, vegetables, and high-fibre grains.

Smoking and Drinking

Smoking and excessive drinking increases your risk of colon cancer. There are many harmful chemicals in cigarettes that enter your bloodstream when you take that puff. While it is best to cut them out altogether, limiting your consumption of alcohol and tobacco will also do wonders when it comes to reducing cancer risks.


Although colorectal cancer can be diagnosed at any age, most colon cancer patients are above the age of 50. In fact, the rates of colon cancer in people younger than 50 have been increasing, but doctors are not sure why yet.

Signs & Symptoms

Most people with colon cancer experience no symptoms in the early stages of the disease. Regular screening can detect polyps or colorectal cancer early, and cancer diagnosis and treatment can happen sooner than later. Once the symptoms appear, they can vary depending on the tumour’s size and location.

The symptoms of colorectal cancer include:

  • Weakness or fatigue
  • The sensation of a full bowel despite defecating
  • Rectal bleeding or blood in your stool
  • Sudden/unexplained weight loss
  • Persistent abdominal discomfort

If you notice any of these persistent symptoms that worry you, please make an appointment with your doctor at a cancer management centre.

It’s recommended that you talk with your doctor about when to begin colon cancer screening. Current guidelines generally recommend that colon cancer screenings begin around 50. Your doctor may recommend more frequent or earlier screening if you have other risk factors, such as a family history of the disease.

Risk Reduction

There are steps that you can take to reduce your risk of colon cancer.

  • Eat a variety of whole grains, fruits, and vegetables
  • Stop smoking and drink alcohol in moderation, if at all
  • Exercise for at least 30 minutes on most days
  • Achieve/maintain a healthy weight

Comprehensive and state-of-the-art colon cancer screening and care are available at International Cancer Specialists (ICS). Contact us at +65-6235-9005 and visit our cancer management centre to consult our Senior Consultant Medical Oncologist and team of oncology specialists who will be glad to be of assistance.