9.JUN.2020 5 MIN READ | 5 MIN READ

The most effective way to reduce risk of colorectal cancer is routine screening, starting at age 50. Find out if you are at risk of colorectal cancer and how to mitigate the risk.

What is colorectal cancer

Colorectal cancer is the most prevalent cancer in Singapore, contributing to 1,200 deaths a year. It is the cancer of the large intestine (colon and rectum) and can develop at any age, but it is more common in older adults aged 50 and above.

Polyps (small benign growths) can develop on the inside of the intestinal walls without causing any symptoms, especially early on. These polyps can be present in the intestine for years before becoming cancerous.

Colorectal cancer screening can detect such precancerous polyps so they can be removed before they turn into cancer, thereby preventing its spread to the rest of the body.


Colorectal cancer symptoms
In between regular screenings, be mindful of these early warning signs of colorectal cancer:

  • A noticeable change in your bowel movements, including diarrhoea, constipation or any significant change in your stool’s consistency
  • Bleeding from the rectum
  • Blood in your stools
  • Chronic discomfort in the abdomen (cramps or pain)
  • Fatigue
  • Unexplained weight loss

Why is colorectal screening the best form of prevention?

It is important to note that symptoms usually don’t arise in the early stages of colorectal cancer. This is why screening is important for early detection so that you can receive timely treatment.

Generally, it is recommended that you go for colorectal cancer screening around the age of 50. However, those who fall under any of the following risks should get checked earlier.

Who is at risk?

Some groups of people are at a higher risk of getting colorectal cancer than others.

1. Age

Colorectal cancer is more common in people above the age of 50. As you get older, there is a higher chance that mutations in your body’s cells evade the immune system and develop into cancer.

2. Family history of colorectal cancer

If one of your blood relatives has had colorectal cancer, you have a higher chance of developing it yourself. In fact, around a third of people who develop colorectal cancer have other family members who have had it. There are some genetically inherited syndromes that confer a significantly higher risk (up to 20 times) of developing colorectal cancer.

3. Chronic inflammatory diseases

Having intestinal conditions like Inflammatory Bowel Disease (IBD), ulcerative colitis and Crohn’s disease may also increase the likelihood of developing colorectal cancer.

In fact, IBD is known to be a significant risk factor in the development of colorectal cancer. According to an article in World J Gastroenterol, chronic inflammation is believed to promote carcinogenesis, which is the start of cancer formation.

4. Low fibre, high-fat diet

Low-fibre diets have been linked to colon cancer. A diet rich in high-fibre food decreases your overall calorie intake and helps you maintain a healthy weight. This is vital to reducing cancer risks.

5. Physical inactivity

A study by JNCI: Journal of the National Cancer Institute found that physical inactivity has been linked with an increase in the risk of certain cancers, including colorectal cancer.

Spending large amounts of time sitting down can still be detrimental even for people who exercise regularly. The risk of developing colorectal cancer increased by 8% with each 2-hour increase in sitting time.

6. Diabetes

Insulin resistance, which is a feature in diabetics, can cause you to have a higher chance of developing colorectal cancer.

7. Obesity

Being overweight doesn’t mean that you will definitely develop cancer, but it does make you more likely to get cancer than if you were of a healthy weight.

According to Gut journal, around 11% of colorectal cancer cases in Europe were linked to obesity and being overweight. Data also suggests that obese men have a 30 – 70% increased risk of developing colon cancer.

8. Smoking

Long-term cigarette smoking is associated with colorectal cancer, even after taking into consideration other risk factors. According to a study by the American Association for Cancer Research (AACR), the incidence of colorectal cancer was significantly higher in current and former smokers.

9. Alcohol

The more you drink, the greater the risk of getting cancer. Even moderate drinking was shown to increase the risk of colorectal cancer. Studies have shown a positive association between alcohol consumption and the risk of polyp formation. The metabolism of alcohol in the body involves ethanol conversion that could have cancerous effects on the colon.


Colorectal cancer prevention
Here are some of the prevention measures that can help reduce the risk of colorectal cancer.

1. Eat a healthy, well-rounded diet

Vitamins, minerals, fibre and antioxidants are important components of a healthy diet to prevent cancer. Including fruits and vegetables in your diet is a good way to absorb these nutrients and reduce your risk of developing cancer. Fruits, vegetables, whole grains and legumes can be eaten to increase your fibre intake.

2. Reduce alcohol consumption

Limit the amount of alcohol you drink. Your chances of developing cancer are significantly larger if you have more than four drinks a day. Having up to 2 drinks for men, and 1 drink for women each day counts as moderate drinking.

One ‘drink’ in this instance would refer to:

  • 30ml of liquor,
  • 140ml of wine,
  • or 340ml of beer.

Reducing alcohol intake may be difficult especially if you are a heavy drinker. Your doctor or counsellor may be able to help you in this. Even your friends and family members can be a source of support if you are trying to cut out alcohol from your life.

3. Quit smoking

Cigarettes contain carcinogens that increase your risk of developing any form of cancer. Nicotine in cigarettes can actually be as addictive as drugs like heroin and cocaine, making it difficult to quit. Around one-fifth of smokers will go through withdrawal symptoms upon quitting. Consult your doctor on a plan to quit smoking and cope with Nicotine Withdrawal Symptoms.

4. Increase physical activity

Reducing the time spent sitting down may be useful in preventing cancer. According to the National Cancer Institute, exercise increases antioxidant levels and helps repair DNA. It can also decrease inflammation and boost your immune system.

When to visit the A&E department

Seek medical treatment immediately from the nearest Accident & Emergency (A&E) department if you are experiencing

  • constant, extreme pain in your abdomen
  • bloating
  • irregular, painful bowel movements
  • difficulty in standing up

An early diagnosis of cancer is key to increasing the chances of survival, successful treatment, and quality of life.

Make the good times last with your loved ones, and learn more about cancer screening or call +65 6812 3396 to make an enquiry.


Article reviewed by Dr Ng Chee Yung, general surgeon at Mount Elizabeth Novena Hospital


Colon cancer. Retrieved on 3 May 2020 from https://www.mayoclinic.org/diseases-conditions/colon-cancer/symptoms-causes/syc-20353669

Chun, C (2019). Everything you need to know about colon cancer. Retrieved on 3 May 2020 from https://www.medicalnewstoday.com/articles/150496#treatment-options

Henrickson, N. (2015) Family history and the natural history of colorectal cancer: systematic review. Retrieved on 8 May 2020 from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4955831/

Kim, E and Chang, D. (2014) Colorectal cancer in inflammatory bowel disease: The risk, pathogenesis, prevention and diagnosis. Retrieved on 8 May 2020 from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4123369/

(2014) Sedentary behavior increases the risk of certain cancers. Retrieved on 8 May 2020 from https://academic.oup.com/jnci/article/106/7/dju206/1010488

Bardou M, Barkun AN, Martel M. (2013) Obesity and colorectal cancer. Retrieved on 8 May 2020 from https://www.ncbi.nlm.nih.gov/pubmed/23481261

Hannan, L. (2009) The Association between Cigarette Smoking and Risk of Colorectal Cancer in a Large Prospective Cohort from the United States. Retrieved on 8 May 2020 from https://cebp.aacrjournals.org/content/18/12/3362

Rossi, M. (2018) Colorectal Cancer and Alcohol Consumption–Populations to Molecules. Retrieved on 8 May 2020 from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5836070/

Ratini, M. (2018) How Drinking Alcohol Raises Cancer Risk. Retrieved on 8 May 2020 from https://www.webmd.com/cancer/cancer-alcohol-cancer-link#2

Ng Chee Yung
General Surgeon
Mount Elizabeth Hospital

Dr Ng Chee Yung is a general surgeon practising at Mount Elizabeth Novena Hospital, Singapore. Dr Ng specialises in colorectal surgery, with a passion in advancing the practice of minimally invasive colorectal procedures.