Learn About Colorectal Cancer

Colorectal cancer has already ranked the top common cancer and second in Hong Kong. The 2014 Policy Address states that the Government will subsidise colorectal cancer screening for higher risk groups. The Department of Health is conducting a study with the HA and will start the preparatory work of a pilot programme soon.

Though colorectal cancer is indentified from people aging from 30-80, the majorities are aged 50 or above. It is indicated in recent statistics that approximately 20% of colorectal cancer cases were diagnosed during the final stage. Most cases are diagnosed in stage 2 or 3 and only less than 10% of in stage 1. The earlier the stage at diagnosis, the higher the post-surgical curability.

Causes and Risk factors

In most people, the cause of colorectal cancer is still unknown. However we know that some factors are associated with an increased risk of developing colorectal cancer:

Age:The risk of colorectal cancer increases with age.

Diet:There is evidence to suggest that cancer of the large bowel may be linked to our diet. It is thought that a diet high in animal fat and low in fibre, may increase the risk of developing cancer of the bowel.

Other environmental factors:Lack of physical activity, obesity, smoking and heavy alcohol intake are all associated with an increased risk of developing the disease.

Family history of bowel cancer:If you have first-degree relatives with bowel cancer, you have an increased risk of developing the disease.

Personal history of bowel polyps or cancer:If you have previously developed bowel polyps or bowel cancer, though these were already removed, your risk of developing the disease again is higher.

Inherited diseases:

Two inherited diseases, known as Familial Adenomatous Polyposis (FAP) and Hereditary Nonpolyposis Colorectal Cancer (HNPCC) Syndromes, are causing around 1% and 4% of colorectal cancer cases. These are inherited in an autosomal dominant pattern. Patients with the former disease will develop hundreds of benign polyps in the colon that eventually progress to cancer. The latter disease is characterised by the development of colorectal cancers at an early stage, and in multiple family members.

The development and metastasis of colorectal cancer

The colorectal cancer cells may develop and invade into normal tissues and metastasize to organs remote from the primary site. As the cancerous tumour grows it erodes the large intestine and leads to colonic obstruction, perforation of the large intestine, or the invasion of the adjacent organs. The colorectal cancer cells can break away from the colorectal tumour and metastasize to other organs such as liver, lung and peritoneum while continuing with the growth and invasion.


There are no symptoms for most polyps and early colorectal cancer. Those with symptoms are usually at later stages.

Common symptoms of colorectal cancer:
  • Pre-rectal bleeding
  • Change in bowel habits
  • Mucus in stool
  • Tenesmus (sense of incomplete emptying)

Symptoms in late stages include:
  • Abdominal pain
  • Abdominal mass
  • Weight loss
  • Colonic obstruction
  • Perforation
  • Lack of appetite

Diagnosis of colorectal cancer

After consultation, clinical examination and Digital Rectal Examination, further investigation will be needed. Methods of diagnosing colorectal cancer include colonoscopy, barium enema and virtual colonoscopy.

Treatments for colorectal cancer
1. Diagnosis Colonoscopy with biopsy OR Barium enema
2. Pre-surgical investigation of metastasis of cancer 1.Chest X-ray plus computer abdominal tomographic Scan (CT Scan) or ultrasound OR
2.Positron emission tomography scan(PET scan)
3.1 OR 2 +/- transrectal ultrasound
3. Body check and estimation of surgical risk Blood test (including carcinoembryonic antigen (CEA), complete blood picture, liver and renal function test) and electrocardiogram, etc
4. Treatments (No metastasis) radical surgery +/- supplementary chemotherapy or radiotherapy
(Metastasized) palliative care (Chemotherapy and radiotherapy. Palliative treatment to reduce obstruction by stenting or resection.

Radical colectomy for colorectal cancer

If the cancer cells did not metastasize to other organs or to the abdominal cavity, the colorectal cancer can be treated by colectomy. Such colectomy are radical. Radical excisional surgery excises the part of large intestine where the tmour situated, as well as the lymphatic tissues which that part of large intestine belongs to. The area to be excised depends on the location of the tumour, blood supply and the distribution of lymph.

Open colectomy for colorectal cancer

The surgery takes place at the incision at the middle of the abdomen. Patients are usually not allowed to eat for a few days after the operation. To relieve wound pain, methods such as epidural analgesia and patient-controlled analgesia may be reinforced. Most patients can walk on the fifth day after the surgery and can be discharged from the hospital on the seventh day.

Laparoscopic assisted colectomy, LAC

Laparoscopic assisted colectomy (also regarded as minimally invasive colectomy) was firstly introduced in 1991. Up to 1998, over 3000 LAC has already been conducted. Nowadays, LAC has become the first choice of experienced minimally invasive surgeons in tackling colorectal cancer. After a long period of studies and evaluation, the feasibility and safety of LAC was proven in the 1990s. Its proven short term advantages include the reduction of pain, the shortening of hospitalization period, the early resume of daily activities, and wounds with better cosmetic outcome. The metastasis rate of the wound is less than 1%, which is similar to that of laparotomy. Starting from 2003, it has been proven in several researches on randomized comparison of post-surgical long-term survival rate that there are no differences between LAC and open colectomy in terms of there recurrence rate and survival rate in tackling different stages of colorectal cancer.

Procedure of LAC:
  • Perform with a laparoscope and a monitor
  • Pump in CO2 (12mmHg) to maintain sufficient space inside the abdominal cavity
  • Long and thin devices specially used in minimally invasive surgery are applied
  • 5 to 6 incisions ranging from 5mm to 12mm are made on the abdomen
  • The area to be excised is the same as that in open colectomy
  • One of the small incision has to be enlarged to 5cm so that the excised part can be taken out

Laparoscopic assisted colectomy vs Open colectomy


  • Less wound pain
  • Faster recovery
  • Patients can resume easting on the day of surgery after the procedure
  • Smaller wounds with better cosmetic outcome
  • Less wound infection
  • The possibility of the occurrence of adhesive small bowel obstruction may be reduced


  • More expensive
  • Longer operative time
  • The technique is difficult to apply and requires training

Laparoscopic assisted colectomy is not suitable for persons who:
  • suffer from serious congestive heart failure (CHF)
  • suffer from type II Respiratory failure, i.e. serious emphysema
  • have undergone several times of laparotomy
  • have a colorectal cancer tumour that is too large so that the incision for the excised part to be taken out is of similar size to the incision of laparotomy.

Laparoscopic assisted colectomy - Common misunderstanding
  • The resection area of LAC and Open colectomy are the same. The recurrence and survival rate of the two treatments are the same.
  • LAC cannot reduce the recurrence, in general. LAC is not exclusively for cancer of early stages
  • LAC is also a kind of major operation and incision is needed. What is not needed is laparotomy or a large incision.
  • LAC reduces the post-surgical wound pain, but it is not pain-free postoperatively.

  • Radiotherapy treats cancer by using high energy rays which destroy the cancer cells while doing as little harm as possible to normal cells.
  • Radiotherapy is used before or after the surgery to treat cancer of the colon and rectum.

  • Chemotherapy is the use of special anti-cancer (cytotoxic) drugs to destroy cancer cells.
  • They work by disrupting the growth of cancer cells.
  • This treatment is used for most people after the surgery to decrease the chances of cancer coming back.
  • The drugs are sometimes given as tablets or, more usually, intravenously (by injection into a vein).

Side Effects

Both radiotherapy and chemotherapy may cause side effects, which may include nausea, vomiting, diarrhoea and sometimes hair loss, mouth sores and small ulcers.

Tips for Chemotherapy and Radiotherapy
  • It is important to drink plenty of fluids and maintain a healthy diet during treatments.
  • If you don't feel like eating you could try supplementing your meals with high calorie drinks, which you can buy from most chemists.
  • Treatment can make you feel tired so try and get as much rest as you can.
  • If you lose your hair it will grow back surprisingly quickly. Many people wear wigs, hats or scarves.
  • Regular mouthwashes are important and the nurse will show you how to do these properly.
  • Radiotherapy does not make you radioactive and it is perfectly safe for you to be with other people, including children, throughout your treatment.

Staging systems and post-surgical survival rate

Even with pathologically confirmed complete resection, there is still 30% of recurrence. There recurrences are most likely due to metastases before resection and was not dectectable in pre-operative or intraoperative assessment. The recurrence rate of colorectal cancer correlates with the stage of cancer. 80% of the recurrence occurs within 2 years after the surgery. The colorectal cancer is regarded as cured if there is no recurrence in 5 years after the surgery.

survival rate
I A 90-95%
II B 50-70%
III C 30-50%
IV D <10%

Pre-surgical or post-surgical chemotherapy and radiotherapy
  • Post-surgical chemotherapy is required for Stage III / Dukes'C colorectal cancer.
  • Post-surgical chemotherapy and radiotherapy are required for stage IIb&III / Dukes'B2&C rectal cancer.

Colorectal Screening

The 2014 Policy Address states that the Government will subsidise colorectal cancer screening for higher risk groups. If you are at a higher risk of colorectal cancer (for example, if you have a strong family of the disease), please consult your doctor for the relevant information about the colorectal examination (if faecal-occult blood test or colonoscopy is appropriate). People aging from 50 or above are recommended to have a regular colorectal check and polypectomy will be performed when necessary. This can improve the treatment outcome and reduce the chances of getting colon cancer.

  • The reliability of laparoscopic assisted colectomy is proven and its advantages are confirmed.
  • Seek medical advices as early as possible, as colonoscopy screening and the excision of adenomatous polyps are more effective than surgery assisted with advanced technology.