Colorectal Cancer

Colorectal cancer refers to cancer which develops in any part of the large colon or rectum

Last modified: November 16, 2021

Quick facts about colorectal cancerQuick facts

  • Most colorectal cancer starts with the development of growths, called polyps, on the inner lining of the intestine.
  • Colorectal cancer is the second most common cancer in Malaysia.
  • 1 in 55 men and 1 in 76 women in Malaysia are at risk of contracting colorectal cancer.

Types of colorectal cancerTypes of colorectal cancer

Colorectal cancer refers to both colon cancer and rectal cancer.

Colon cancer

Colon cancer originates in the large intestine, also known as the colon. In many cases, early signs of colon cancer include non-cancerous polyps in the colon.

Rectal cancer

Rectal cancer develops in the end of the large intestine, known as the rectum. Like cancer found in the large intestine, it can begin with the formation of non-cancerous polyps.

Signs and symptoms of colorectal cancerSigns and symptoms

As signs and symptoms for colorectal cancer can be similar to other common conditions such as haemorrhoids, it’s important to see your GP or healthcare professional if you experience any of the symptoms below. Discussing anything concerning with your doctor as soon as possible can help give you peace of mind and offer the best chance of successful treatment if you receive a colorectal cancer diagnosis.

Symptoms may include:

  • Sudden changes in bowel movements, like diarrhoea, constipation, narrower stools, or stools that contain mucus

  • Unexplained weight loss or loss of appetite

  • Bright red or dark blood in your stool or on the toilet tissue

  • Pain in your stomach with or without swelling

  • Constant gas or bloating in the bowel or rectum

  • A lump or pain around the anus

  • Unexplained anaemia (low iron) which can cause tiredness and breathlessness

Stages of colorectal cancerStages

The TNM system is used to stage colorectal cancer, and it helps doctors understand what your cancer looks like. The TNM stands for:

  • Tumour – The degree to which the tumour has affected other tissue, for example has it grown outside the wall of the rectum or colon
  • Node – Is a measure of whether lymph nodes have been affected
  • Metastasis – The degree to which the cancer has spread to other organs of the body

The TNM information, along with other tests, helps determine the stage of your colorectal cancer using the guidelines below:

Stage O

The cancer is in its earliest stage and has not spread beyond the inner layer (mucosa) of the colon and rectum.

Stage I

The cancer has been found in the mucosa, and has spread beyond the inner layer of the colon or rectum to the submucosa, but not to the lymph nodes.

Stage II

The cancer has spread beyond the layer of muscle surrounding the bowel and reached the outermost layers of the colon or rectum and surrounding areas, but has not spread to the lymph nodes.

Stage III

The cancer has spread to the lymph nodes, but not to distant organs.

Stage IV

The cancer has spread to distant organs (e.g. lung, liver, peritoneum) throughout the body.

Treatment for colorectal cancer

There are many different types of treatment for colorectal cancer. Your treatment will depend on you and your cancer.

Frequently asked questions about colorectal cancerFAQs

Is colorectal cancer hereditary?

Approximately 30% of colorectal cancer cases are related to genetics and family history.

There are three common inherited disorders that have been linked to colorectal cancer, including:

  • MYH – Associated Polyposis (MAP) – This is caused by a genetic mutation in the gene MYH gene which results numerous (10-100) polyps (abnormal tissue growth) which can become cancerous.
  • Hereditary Non-Polyposis Colorectal Cancer (HNPCC) (known as Lynch Syndrome) – This results in mutations to the genes that protect cells from growing abnormally and turning into cancerous cells.
  • Familial adenomatous polyposis (FAP) – This is characterised by significant numbers (100 – 1000) of adenomatous polyps (gland-like tissue growths) in the lining of the large intestine.
What causes colorectal cancer?

The cause of colorectal cancer is not fully known, however there are some factors which contribute to the risk of colorectal cancer developing, including:

  • Age – The risk for colorectal cancer increases for people over 50 years.
  • Certain life-style related factors – Such as being overweight, drinking alcohol, a diet high in processed and red meat, and smoking.
  • Family history – Including colorectal cancer and colorectal diseases like Crohn’s disease or ulcerative colitis.
How common is colorectal cancer?

Colorectal cancer is the second most common cancer in Malaysia. It affects both men and women, young and old, with the disease being more common in people older than 50.

What can I do to decrease my risk of colorectal cancer?

There are a number of lifestyle-related factors you can consider to reduce your risk of developing colorectal cancer, like:

  • Get regular exercise – The World Health Organisation recommends at least 150–300 minutes of moderate-intensity aerobic physical activity a week.
  • Reduce your alcohol intake – If you choose to drink, try to limit your alcohol intake to no more than two standard drinks a day.
  • Eat a healthy, balanced diet – Eat a fibre-rich diet from grain and legume sources, as well as enjoy a variety of fruit (2 serves) and vegetables (5 serves) per day, limit your intake of salt, saturated fats, and avoid all processed meat.
  • Regular screening for colorectal cancer – The Ministry of Health Malaysia recommends asymptomatic individuals aged 50 to 75 years to screen for colorectal cancer screening using Immunochemical Faecal Occult Blood Test (iFOBT). The test helps to detect blood in the stool and if the test result from iFOBT is positive, a colonoscopy is recommended. The current recommended screening interval for IFOBT is once every two years.
How do you know if it’s colorectal cancer or haemorrhoids (piles)?

Haemorrhoids, or piles, are soft lumps of enlarged blood vessels around and inside the anus. They usually result from a sudden increase in pressure – such as during pregnancy, constipation, or heavy weightlifting. Symptoms of haemorrhoids can include:

  • Painful bowel motions
  • Bright red blood on toilet tissue, or in the stool
  • Extreme itching around the anal area
  • A lump or swelling around the anus

Because the symptoms of haemorrhoids and colorectal cancer can be similar, it is extremely important to see your GP or healthcare professional if you are experiencing any symptoms of haemorrhoids or colorectal cancer so that a diagnosis can be made.

Where can I find out more about colorectal cancer screening?

For more information on colorectal cancer screening, you can have a look at National Cancer Society Malaysia.


For a full list of references, click here.
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