Understanding colorectal cancer

At Icon Specialist Centre Hong Kong we offer the latest in treatment methods and technologies for a range of colorectal conditions.

Our experienced team of colorectal surgeons are dedicated to delivering exceptional care and supporting you through your diagnosis, treatment, and beyond.

Understanding colorectal cancer

If you have been diagnosed with colorectal cancer, it’s normal to feel a bit overwhelmed by the amount of new information people are sharing with you.

Knowing more about your cancer and what to expect before and after treatment can help you prepare. The following information outlines what your cancer is and how it is diagnosed and treated.

We encourage you to speak to your doctor and care team, who are here to support you throughout your time at Icon.

We will always have time to talk to you and answer your questions.

About colorectal cancer

Colorectal cancer occurs when abnormal cells grow uncontrollably in the large bowel or rectum, forming a cancerous tumour.

Colorectal cancer can be described in stages depending on how early or advanced the cancer is. These include:

  • Stage 0 – The cancer is in its earliest stage and has not spread beyond the inner layer (mucosa) of the colon or rectum
  • Stage I – The cancer has been found in the mucosa, and has spread beyond the inner layer of the colon or rectum wall to the submucosa, but has not spread 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


Cancer screening plays an important role in identifying colorectal cancer in people who do have any signs or symptoms. The Hong Kong Colorectal Cancer Screening Program is open to eligible people between 50 and 75 years of age – who will have the opportunity to perform a stool occult blood test to check for any blood particles within the stool (a potential sign of colorectal cancer).

For people who have symptoms of colorectal cancer or the diagnosis is uncertain, a full examination of the colon is required. The two tests used for this are:

  • Colonoscopy – A colonoscopy involves inserting a camera on a flexible tube into the rectum to examine the entire large bowel. Most commonly patients with severe iron deficiency anaemia and minimal bowel symptoms are diagnosed through colonoscopy. It can be used for both diagnostic and therapeutic purposes, with the ability to obtain tumour biopsies, stop tumour bleeding and place stenting to relieve obstruction.
  • CT colongraphy – CT colonography (or virtual colonoscopy) uses a CT scanner to produce 3D images of the large bowel and rectum, and provides a less invasive option for people who are unable to have a colonoscopy. However, a colonscopy may still be required if a biopsy needs to be taken.

Further tests

If bowel cancer is diagnosed, further tests are usually carried out to see if the cancer has spread beyond the colon or rectum.

These tests can include:

  • MRI scan
  • CT scan
  • PET scan


Treatment for colorectal cancer depends on the type and size of the cancer, and your age, general health and treatment preferences. The most common treatment for colorectal cancer is surgery, which may be provided alongside chemotherapy, radiation therapy or targeted therapies.


The surgical procedure used to treat colorectal cancer is a colorectal resection (colectomy), which involves the removal of all or part of the colon. The two techniques for a colectomy include:

  • Open colectomy – where the surgeon makes a large incision through the skin and abdominal wall to remove a section of the colon
  • Laparoscopic (keyhole) colectomy – a less invasive procedure where the surgeon makes a number of small incisions in your abdomen and uses special instruments guided by a camera to remove a section of colon

While both techniques are effective at removing cancer, laparoscopic surgery is now the routine technique used for colorectal resection, providing advantages including reduced blood loss, postoperative pain and wound infection, a faster recovery from surgery and shorter hospital stay.

Common questions

It’s natural to want to know more about your cancer when first diagnosed. We’ve included some common questions that patients ask about colorectal cancer to help you. Your treatment team at Icon can also answer any additional questions that you have at any point in time.

What are the symptoms of colorectal cancer?

Not everyone experiences symptoms of colorectal cancer, however some common signs include bright red or dark blood in your stool, sudden changes in bowel motions (such as diarrhoea, constipation, having narrower stools or stools that contain mucus), weight loss, abdominal discomfort or bloating, unexplained anaemia (low iron) causing tiredness and breathlessness, and a lump or pain around the anus.

What causes colorectal cancer?

Certain risk factors can play a role in the development of colorectal cancer. These include:

  • Age – People aged 50 or above are more likely to develop colorectal cancer
  • Diet – Diets with high animal fat, high protein and low fibre may increase the risk of colorectal polyps or colorectal cancer
  • Family history – A person who has one or more family members with colorectal cancer may have a higher risk of developing the disease
  • Colorectal polyps – Size, quantity and degree of cell change (dysplasia) of polyps can increase the risk of colorectal cancer
  • Smoking
  • Colorectal disease history – previously having diseases such as Crohn’s disease or ulcerative colitis significantly increases your risk

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