Cancers of the intestine occur most frequently at the
colon and rectum. Colorectal cancer is highly treatable
and often curable when it is localised and diagnosed at
its early stages.
How Common Is Colorectal Cancer?
In Hong Kong, colorectal cancer was the second most common cancer after lung cancer in men, and after lung and breast cancers in women. In 2021, the incidence of colorectal cancer was 80 per 100,000. The median age at diagnosis was 68 years for both males and females.
What Are the Causes And Risk
Factors?
- Age: Colorectal cancer is more common in those
above the age of 40.
- Family and personal history: Those with a family
history of colorectal cancer (especially among first
degree relatives) and familial polyposis coli are at a
higher risk. Women who have a history of ovarian or
breast cancers have a slightly increased risk.
- Polyps: These are non-cancerous growths of the large
intestine. While they are very common in people over
50, one type of polyps referred to as adenomatous
polyps is considered to be a precursor to cancer.
- Those with inflammatory bowel diseases like Crohn’s
disease and ulcerative colitis have a higher risk of
developing colorectal cancer.
- Diets high in fat, low in fibre and lack of exercise
are associated with an increased risk of having
the disease.
What Are the Common Symptoms?
Common symptoms of colorectal cancer include:
- Anemia
- Change of bowel habit like constipation or diarrhea
and blood in the stool
- Abdominal pain and vomiting
- Weight loss and tiredness
Although these symptoms can be caused by other
conditions, it is very important that you always have
them checked by a doctor.
How Does the Doctor Make the
Diagnosis?
The following procedures are indicated for patients who
are suspected to have colorectal cancer:
- Physical examination: This includes digital rectal
examination in which the doctor inserts a lubricated,
gloved finger into the rectum to feel for a lump and
abdominal examination for a mass or enlarged liver.
- Blood test: This includes the fecal occult blood test
to test for hidden blood in the stool and blood test
for anemia and CEA, a tumour marker that may be
elevated in people with colorectal cancer.
- Barium enema is a special form of X-ray used to
show the contour of the large intestine and hence any
abnormal area.
- Colonoscopy and biopsy: A flexible tube called
a colonoscope will be passed into the rectum to
look inside the whole length of the large intestine.
Samples will be taken for biopsy in which cells or
tissues will be examined under the microscope for
abnormalities.
- CT scan or PET scan to identify distant metastasis.
How Is Colorectal Cancer Treated?
The following types of treatment may be given alone or
together, depending on the patient’s condition:
- Surgery is the primary treatment for colorectal
cancer. A recent advance is the introduction of the
minimally invasive surgical technique with the benefit
of having small wounds and quick recovery. When
cancer occurs in the lower part of the rectum, a
colostomy (an artificial opening of the bowel) may
be required after surgical removal of the tumour.
- Chemotherapy: Currently available chemotherapy
does not completely eradicate primary colon cancer.
Adjuvant chemotherapy to eradicate micro-metastasis
that is not visible at the time of surgery has been
shown to be useful in preventing future relapse. In
advanced colon cancers, chemotherapy is used to
improve the survival.
- Radiotherapy: Adjuvant radiotherapy has been
shown to decrease local recurrence of rectal cancer.
Combined radiotherapy and chemotherapy increases
disease-free survival for rectal cancer more than
radiotherapy alone.
Doctors will plan the most appropriate treatment
according to the patient’s condition.
Is There Any Method to Screen for
Colorectal Cancer?
It is recommended to start colonoscopy around the age
of 40 and repeat every 5 years if the first examination is
normal. Yearly digital rectal examination and fecal occult
blood test are also recommended.
We provide a colorectal cancer screening package for
the high-risk group. Procedures consist of basic physical
examination, medical history taking, digital rectal
examination, abdominal examination, fecal occult blood
test, colonoscopy / virtual colonoscopy and follow-up.
Please contact us for details.
How Can Colorectal Cancer Be
Prevented?
Colorectal cancer is the most likely of all cancers that
can be prevented through a healthy diet and lifestyle.
This means having a well-balanced diet, cutting down
on high-fat food, and performing regular physical
exercise. As most colorectal cancers grow through the
stage of a polyp, colonoscopic removal of the polyp can
prevent this type of cancer from occurring.