The causes

A number of factors are believed to increase the risk of getting the condition.

• Diet: It is thought that a diet high in animal fat and protein, and low in fibre, may increase the risk of developing colorectal cancer.

• Lifestyle factors: Obesity, lack of exercise, smoking and excessive alcohol consumption may also increase the risk of developing this cancer.

• Family history: People with a family history of colorectal cancer may have an increased risk of developing the condition. Those who have more than one family member diagnosed with colorectal cancer, or whose parents or siblings developed colorectal cancer under the age of 45, also have a higher risk.

The symptoms

If you are experiencing some or all of these symptoms, you may have problems with your bowel. However, in its early stages colorectal cancer often has no symptoms and can go unnoticed. To ensure early detection, consult your doctor.

• Blood or mucus in your stool

• Changes in bowel movements lasting for more than two weeks (alternating between diarrhoea and constipation, stool becoming very narrow, a sense of incomplete emptying after a bowel movement)

• Constant abdominal discomfort (colicky pain, fullness or cramps)

• Unexplained weight loss

Colorectal cancer may also cause ileus (an inability of the muscles in the large bowel to push along digested food). The symptoms of this include constipation, abdominal pain and bloating.