10 things you should know about colorectal cancer

Understand colorectal cancer better so that you can lower your risk of getting it, says Dr Zee Ying Kiat of Parkway Cancer Centre

Did you know that colorectal cancer is one of the top cancers in Singapore? The good news is, you can do your part in preventing it.

Here are 10 things you should understand about colorectal cancer so you can take action towards its prevention:

1. Why do I need to be aware of colorectal cancer?

Colorectal cancer is cancer that occurs in the colon (large intestine) or rectum (lower part of the large intestine). It mainly affects people above the age of 50.

According to the Singapore Cancer Registry, about 1,500 patients are diagnosed with colorectal cancer annually. About 650 patients die from it each year.

In Singapore, colorectal cancer is the:

  • No. 1 most common cancer in men (about 1 in 6 of male cancer patients)
  • No. 2 leading cause of cancer deaths in men
  • No. 2 most common cancer in women (about 1 in 7 of female cancer patients)
  • No. 3 leading cause of cancer deaths in women 

2. What causes colorectal cancer?

In most cases, colorectal cancer begins as benign polyps (non-cancerous growths) on the inner wall of the colon or rectum that develop into malignant tumours over a period of five to 10 years.

Colorectal cancer occurs in the colon or rectum, which are parts of the large intestine.

3. What are the symptoms?

Although more than half the people diagnosed with colorectal cancer have no symptoms, here are some signs to look out for:

  • Change in bowel habits (diarrhoea or constipation)
  • Presence of blood in your stool
  • Persistent abdominal discomfort
  • Feeling of bowel not emptied completely
  • Constantly feeling full or bloated
  • Unexplained weight loss
  • Having nausea or vomiting

Most often, these symptoms are not due to cancer and could be caused by other health problems. But if you have these symptoms, do see a doctor to be diagnosed and treated as early as possible.

Some of the more common symptoms of colorectal cancer include change in bowel habits and persistent abdominal discomfort. PHOTO: PARKWAY CANCER CENTRE


4. Who are at risk?

The risk of developing colorectal cancer increases if you:

  • Have a family member who has had colorectal cancer
  • Are above 50 years old
  • Have polyps in your colon or rectum (most are benign but some can develop into cancer)
  • Smoke, or consume a diet that is high in fat, red meat, processed meats and low in fruits and vegetables.

5. Why is colorectal cancer so common?

Colorectal cancer is becoming more common, not just in Singapore but also around the world, mainly because of the increase in the following lifestyles and diets:

  • Obesity
  • Smoking
  • Consumption of alcohol
  • High-fat diet
  • Increased consumption of red and processed meats
  • Lack of exercise

6. Can colorectal cancer be prevented?

It is possible to prevent colorectal cancer.

Regular colorectal cancer screening is one of the most powerful weapons for preventing colorectal cancer.

Precancerous polyps can be present, often without symptoms, in the colon for years before invasive cancer develops. Colorectal cancer screening can find precancerous polyps so they can be removed before they turn into cancer. In this way, colorectal cancer is prevented.

Some studies suggest that people may reduce their risk of developing colorectal cancer by increasing physical activity, maintaining a healthy weight, taking more dietary fibre, limiting red and processed meat, limiting alcohol consumption and avoiding tobacco.

7. How is colorectal cancer detected if most patients have no symptoms?

Timely colorectal cancer screening can help your doctor detect and remove the polyps before they become cancerous. Early detection of colorectal cancer can also enable more effective treatment.

If you are 50 years old or older, you should go for:

  • Faecal Immunochemical Test (FIT) once every year — for detection of hidden blood in the stool.
  • Colonoscopy once every 10 years — for examination of the colon and rectum via a long, lighted tube (colonoscope).

If you have a family or personal history of colorectal cancer, you should:

  • Start screening at 50, or 10 years before the youngest family member had colorectal cancer, whichever is earlier.
  • Get a colonoscopy done every one to three years.

8. What can happen if colorectal cancer is left undetected?

If the small, non-cancerous polyps in the large intestine are detected early, they can usually be removed via colonoscopy.

But if left undetected, they could develop into cancer that may spread to other parts of the body.

9. What treatment options are available?

An important step following the diagnosis of colorectal cancer is to determine its stage.

Cancer stage refers to the extent of a cancer in the body. The staging of colorectal cancer is based on the size of the tumour, whether lymph nodes contain cancer and whether the cancer has spread from the original site to other parts of the body (such as the liver).

Stage I represents the earliest stage of cancer while Stage IV represents the most advanced stage, where the cancer has spread to other parts of the body.

Development stages of colorectal cancer. ILLUSTRATION: PARKWAY CANCER CENTRE

Different types of treatment are available for patients with colorectal cancer. Broadly, these treatments are:

  • Surgery
  • Chemotherapy
  • Radiotherapy
  • Targeted therapy
  • Immunotherapy

The type of treatment recommended will depend on several factors, including the cancer stage and overall health of the patient.

10. What should I do to minimise my risk?

You can lower your risk of colorectal cancer by making simple dietary and lifestyle changes such as:

  • Quit smoking
  • Limit your alcohol intake
  • Eat a diet that is low in saturated fats, red meats and processed meats
  • Eat more fruits, vegetables and whole grains
  • Exercise regularly
  • Maintain a healthy weight

Just as importantly, go for appropriate screening for colorectal cancer.

Find out more about colorectal cancer here.

Brought to you by Parkway Cancer Centre