Bowel cancer is the third commonest cancer and the second commonest cause of cancer death ⁽¹⁾ in Britain.

Bowel cancer can be simple to treat, if the disease is diagnosed at the earliest stage, with slightly over 80 per cent of patients ⁽²⁾ surviving for more than five years.

The majority of bowel cancers develop in the large bowel - two-thirds ⁽³⁾ of these are in the colon and one-third in the rectum. While a diagnosis of any cancer is serious, if bowel cancer is diagnosed early, you have an excellent chance of being completely cured.

What is the bowel and what does it do?

The bowel is part of the digestive system and is divided into two parts:

1. Small bowel
2. Large bowel (colon and the rectum).

The large bowel is the lower part of your gut which absorbs water and essential nutrients as digested food moves through your body.

The colon is divided into three sections:

1. Ascending colon
2. Transverse colon
3. Descending colon

The rectum (back passage) is the last part of your colon where stools (faeces) are held until passed out of your body as a bowel motion.

My doctor found some polyps in my colon. Do I have colon cancer?

A polyp is a small growth on the inside of the bowel wall which becomes more common with age - one in 10 people over 60 ⁽⁴⁾ have polyps. If you have polyps, it doesn't mean you have colon cancer.

Although bowel cancer usually develops from a polyp, most polyps are benign (non-cancerous). About one polyp in 10 ⁽⁵⁾ will turn into a cancer. If the doctor decides to remove a polyp, it is sent away to be analysed in a laboratory to check it is non-cancerous.

How do I know if I have bowel cancer?

Early on, you may be no symptoms at all. If symptoms do develop, they can include the following:

• A persistent change in bowel habit - especially going more often or with looser stools for several weeks, or an increase in the amount of mucus in the stool
• Bleeding from the bottom
• Persistent constipation
• Abdominal pain, especially if severe
• A lump or swelling in your abdomen
• Other symptoms include unexplained anaemia causing tiredness or weight loss

Remember that many of these symptoms will not be cancer, but if you have one or more for over four to six weeks you should consult your GP.

What causes bowel cancer?

Nobody really knows what causes bowel cancer. People who develop bowel cancer are normally aged over 65 years ⁽⁶⁾, and the frequency of the disease increases with age.

Few younger adults ⁽⁶⁾ from the age of 20 get bowel cancer. There are certain risk factors, however, many of which are associated with lifestyle.

Controllable risk factors:

• Obesity
• Eating too much fat and processed food which is low in fibre. Not eating enough fruit and vegetables
• Smoking
• High alcohol intake
• Inactivity

Uncontrollable risk factors:

• Some inflammatory bowel diseases, such as colitis, can lead to bowel cancer
• 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 ⁽⁶⁾

What are the inherited types of bowel cancer?

There are two rare inherited conditions that can increase the risk of developing bowel cancer:

1. familial adenomatous polyposis (FAP)
2. hereditary non-polyposis colorectal cancer (HNPCC)

About 10 per cent of bowel cancers ⁽⁶⁾ have a strong genetic factor.

What can I do to reduce risk?

• If there is a family history of bowel cancer, you may be eligible for regular screening ⁽⁷⁾
• Drink plenty of water
• Eat a high fibre, low fat diet, with at least five portions of fresh fruit and vegetables a day
• Be aware of your bowel movements, so you know what's normal for you
• Take regular exercise

How is bowel cancer diagnosed?

Your doctor may give you a rectal examination with a gloved finger to feel for any suspicious lumps in the rectum. You may also have a blood test to check for anaemia.

Other diagnostic tests:

• Colonoscopy or sigmoidoscopy allows a doctor to look inside your bowel through a tube with a tiny camera on the end (colonoscope) to see if there is part of the lining which looks out of the ordinary. A sigmoidoscopy examines the lower part of your large bowel, while the colonoscopy looks all the way round the colon. The doctor can take photographs and samples (biopsies) of the cells or any polyps they find on the inside of the large bowel during the test
• Barium enema is an examination using barium (a thick white liquid). The enema is passed into the back passage through a tube and under X-ray, any abnormal areas can be seen
• Other tests include an abdominal ultrasound, CT scan or MRI scan. These tests will show the size of the cancer, its position and whether it has spread

What are the different bowel cancer stages?

The Dukes System ⁽⁸⁾ is used by doctors to describe the different stages of large bowel cancer.

• Dukes A: the cancer is contained within the bowel wall
• Dukes B: The cancer has spread through the muscle of the bowel wall, but has not spread to the lymph nodes
• Dukes C: The cancer has spread to one or more of the lymph nodes close to the bowel
• Dukes D: The cancer has spread (metastasised) to other parts of the body, such as the lungs or liver. These cancers are called secondaries.

The TNM staging system ⁽⁸⁾ is gradually replacing the Dukes System, because it provides more detailed information about the different stages of tumour formation and spread.

TNM provides more detail about the tumour stage:

• T describes tumour size and if it has spread into the bowel wall
• N describes if the cancer has spread to the lymph nodes
• M describes if the cancer has spread to another part of the body

What's the treatment for bowel cancer?

There are three standard treatments for bowel cancer, which can be used alone or in combination with each other, depending on how big the cancer is, its position and whether it has spread.

• Surgery is either open or laparoscopic (keyhole) surgery. When possible, the cancer, surrounding bowel and tissues will be removed and the two ends of the bowel joined back together
• If there isn't enough of the bowel left to be joined together, you may need a temporary or permanent colostomy (stoma). This is an artificial opening where the healthy part of your bowel is brought to the surface of your abdomen. A bag is attached to this opening and bowel waste can be collected
• Radiotherapy can be used to shrink a tumour that is causing pain. It is most often used for rectal cancers. It may also be used to reduce the risk of cancer returning after surgery or to treat cancer if it comes back
• Chemotherapy is sometimes given before surgery. When it is given after surgery, it may be over a period of six months, as an outpatient. If an operation isn't appropriate for you, then chemotherapy may be used on its own. Chemotherapy is the most commonly used treatment for advanced-stage bowel cancer

What is life like after bowel cancer?

After your treatment has finished, you will have regular check-ups, which can include scans, blood tests, X-rays or colonoscopies.

If you have any new symptoms or experience problems with side effects, you should let your medical support team know as soon as possible.

You should still be able to eat and drink as normal (with alcohol in moderation).

After surgery, men may find it difficult to obtain or maintain an erection and women may experience pain during intercourse. If this is likely to be a problem, it should be discussed before the operation goes ahead.

Infolinks:

• Bowel Cancer UK
• Beating Bowel Cancer
• Core (Digestive Disorders Foundation)
• Association for International Cancer Research
• Cancer Research UK
• Cancerhelp
• CancerBACUP
• Macmillan Cancer Support
• British Colostomy Association
• Colon Cancer Concern (CCC)