This is an attempt to explain what large bowel cancer is, symptoms, possible causes,how it is diagnosed and how it may be treated. This information does not replace the discussion between you and your doctor but helps you to
understand more about what is discussed. It may also help you in making some important decisions about your condition.
The Digestive system
To understand large bowel cancer it helps to have some knowledge of how your body works.
When food is eaten, it passes from the mouth down the oesophagus (food pipe) into the stomach. In the stomach it is broken down and becomes semi-liquid. It then continues through the small intestine (small bowel), a coiled tube many feet long where food is digested and nutrients (things your body needs) are absorbed.
The semi-liquid food is then passed into the colon (large bowel), a wider, shorter tube, where it becomes faeces (stools). The main job of the colon is to absorb water into our bodies making the faeces more solid. The stools then enter a storage area called rectum. When the rectum is full, we get the urge to open our bowels. The stools are finally passed through the anus (back passage) when going to the toilet.
What is Bowel Cancer?
The term ‘bowel cancer’ or large bowel cancer is used to describe both:
Cancer of the large bowel (colon)
Cancer of the back passage (rectum).
These cancers are generally known as colorectal cancers.
How does this bowel cancer develop?
Bowel cancer usually develops from a polyp in the bowel. A polyp is a
type of growth that forms in the lining of the bowel. Most polyps remain
benign ( non-cancerous) but, if left untreated, some may turn into a cancerous tumour. Removal of polyps can prevent bowel cancer.
What causes cancer of the bowel?
Little is known regarding the cause of bowel cancer, although we are
aware of some risk factors. Most of these are associated with lifestyle:
‘Western’ type diet – high meat intake (particularly processed meat: sausages, bacon, burgers and ham). Low intake of vegetables and possibly fruit.
Smoking & Obesity ( Excess overweight)
Some inflammatory bowel diseases.
A family history of bowel cancer – if two or more members of your immediate
family have had bowel cancer or one member of your family was diagnosed
under the age of 45.
What are the symptoms of bowel cancer?
Symptoms vary according to the position and size of the cancer. The
following can be possible symptoms of bowel cancer and include:
A persistent change in bowel habit for six weeks such as: going to the
toilet more often, or trying to go, looser or more diarrhoea like stools or severe constipation. Repeated bleeding from the back passage or blood in the bowel
motion with no anal symptoms (no irritation, lumps, straining with hard stools or soreness)
Unexpected weight loss.
Anaemia (unexplained tiredness and fatigue due to a low level of red blood cells).
An unexplained lump in the tummy.
These symptoms do not definitely mean that someone has bowel cancer, however, they should always be taken seriously and properly investigated.
How do I know I have bowel cancer?
Bowel cancer is usually diagnosed using the results from a number of
tests and investigations:
Tests with a specialised flexible telescope (Colonoscope) to look inside the bowel.
X-ray tests and CT scan and or MRI scans.
How is bowel cancer treated?
There are three standard types of treatment for bowel cancer.
These are surgery, radiotherapy and chemotherapy. Each of these can be used
alone or in combination with each other, depending on the extent and
location of the disease.
When a diagnosis of bowel cancer is made, each individual case is
discussed with specialists who will consider which treatment(s) may be the best option.
Following this your consultant surgeon will discuss the results of your investigations and treatment options with you. Your surgeon will also answer any questions you have on the benefits and risks of these treatments. Once a treatment plan has been agreed with you, the team should be able to offer you to start treatment straight away.
What type of surgery is performed?
The type of operation performed depends on the extent and position of
your cancer. Where possible the cancer and surrounding bowel and
tissues will be removed and the two ends of the bowel joined back
together. Sometimes a stoma (bag on the tummy to collect bowel
waste) ( Colostomy or Ileostomy) may need to be performed; this can be temporary or permanent.
Following surgery a pathologist examines the piece of bowel removed.
The pathologist describes the growth of the cancer according to a
system called Dukes staging. This is explained in the table below:
Dukes stage :
A : Cancer is confined to the wall of the bowel.
B : Cancer has spread through the wall of the bowel.
C : Cancer has spread to lymph nodes. It will probably
although not always, have spread through the bowel wall.
D : Cancer has spread to other sites, often the liver.
What is Radiotherapy? or Radiation treatment?
Radiotherapy involves directing a beam of radiation at the cancer; it is
similar to having an X-ray. Radiotherapy is usually given on a daily basis as an out-patient over a period of time. Each treatment takes just a few minutes to complete and is painless.
Courses of treatment are short (five days) or long (four to six weeks).
Radiotherapy can be used to:
Shrink rectal cancer prior to surgery.
Relieve symptoms if surgery is not appropriate.
Reduce the risk of a cancer coming back after surgery.
Treat cancer if it comes back after surgery.
What is Chemotherapy?
Chemotherapy is a systemic treatment in that it treats the whole body.
It involves the use of anti-cancer drugs to destroy cancer cells or stop
them from multiplying.
Chemotherapy may be given with long course radiotherapy before
surgery. Chemotherapy given after surgery is usually over a period of about six months as an out-patient. Sometimes chemotherapy is used instead of surgery if an operation is judged not to be suitable.
Drugs may be given by injection into a vein or by mouth in a tablet form.
Often people who have seemingly the same disease have different treatments. This is because tumours can be of different sizes, different types and in different parts of the bowel and/or body. If chemotherapy is suggested, a consultant oncologist will explain which anti-cancer drugs are suitable for you and discuss the aims of treatment and any possible side effects.
What are Clinical Trials?
Research is continuing to find new or better ways of treating bowel cancer. All new drugs and treatments are developed through clinical trials. You may be asked to participate in these. This is completely voluntary and would be discussed with you in detail. If you have any questions at all, please ask your consultant surgeon, oncologist or colorectal nurse. It may also help to write
down questions as you think of them so you have them ready and bring someone with you when you attend your outpatient appointments.