Bowel cancer is also known as colon, rectal or colorectal cancer. The lining of the bowel is made of cells that are constantly being renewed. Sometimes these cells grow too quickly, forming a clump known as a bowel polyp or an adenoma. Polyps are usually benign. Although they are not bowel cancers they can change into a malignant cancer over a number of years. A malignant cancer is when cancer cells spread beyond the original site and into other parts of the body.
What are the symptoms of bowel cancer?
The most common symptoms of bowel cancer are:
- a persistent change in bowel habit, especially needing to go to the toilet more often or having diarrhoea for several weeks
- bleeding from the back passage or blood in the bowel motion
- severe abdominal pain
- a lump in the abdomen
- unexplained tiredness or weight loss
These symptoms do not necessarily indicate bowel cancer, but if one or more persists for four to six weeks then the GP should be consulted.
How many people get bowel cancer? (Incidence)
There were 37,514 new cases of bowel cancer diagnosed in England in 2009, 18,538 males and 15,066 females. This represents rates of 57.3 per 100,000 males, 37.6 per 100,000 females and 46.6 per 100,000 overall.
How many people die of bowel cancer? (Mortality)
In 2010, there were 7,170 male deaths from bowel cancer and 5,993 female deaths in England. These represent a rate of 20.9 per 100,000 (male), 12.8 per 100,000 (female) and 16.4 per 100,000 overall.
What is the lifetime risk for bowel cancer?
The lifetime risk of developing bowel cancer for men is around one in 15. For women, it is around one in 19.
For more detailed statistics about bowel cancer please see Cancer Research UK.
What are the risk factors?
- Age: Bowel cancer can occur in younger people but 8 out of 10 people who get cancer of the bowel are over the age of 60.
- A previous bowel polyp
- Personal history of chronic bowel inflammation: Ulcerative colitis and Crohn’s disease will slightly increase the risk of developing bowel cancer.
- Diet: A diet that is high in red meat and fat and low in vegetables, folate and fibre may increase the risk of bowel cancer.
- Lack of exercise: Moderate exercise may help prevent bowel cancer.
- Obesity: Being overweight or obese may increase the risk of bowel cancer.
- Smoking and alcohol: Although not as strong a risk factor as for other cancers, smoking may also increase the risk of bowel cancer, particularly in heavy drinkers. Alcohol consumption may increase risk, especially in those with low levels of folate in their diet.
- Family history: Fewer than 1 in 10 cases of bowel cancer are due to an inherited gene defect. However, there are certain families who have an increased risk of developing bowel cancer due to a variety of conditions including familial adenomatous polyposis (FAP) and hereditary non-polyposis colon cancer (HNPCC).
- Personal history of bowel cancer: Having had bowel cancer before increases the risk of a new cancer developing.
For a more detailed discussion of the risk factors see Cancer Research UK – risk factors.