Many people worry about getting bowel cancer, sometimes because a relative has had it. About 1 in 20 people will get bowel cancer in their lifetime.
Bowel cancer is the third most common cancer in the UK for men and the second most common cancer for women. Every year more than 30,000 people will develop it.
The cause of most bowel cancers is not known, but we do know that some risk factors can increase your chances of developing cancer.
Having a particular risk factor for cancer, or being exposed to one, doesn’t mean that you will definitely get cancer – just as not having it doesn’t mean that you won’t. For example if you just have one elderly relative who had bowel cancer, it’s unlikely that you will have a significantly increased risk.
How does family history affect my bowel cancer risk?
Genes carry the biological information we inherit from our parents. They affect the way our bodies grow, work and look.
Changes (mutations) in certain genes can increase the risk of bowel cancer in family members who inherit the genetic change. However, only a small number of bowel cancers are thought to be due to an inherited altered gene (genetic mutation) running in the family.
A genetic mutation that could increase your risk of developing bowel cancer is only likely to be present in your family if you have:
- One close relative who had bowel cancer at a young age (under 50). Your close relatives are your parents, children, brothers and sisters. They are also sometimes called your first degree relatives.
- At least two first degree relatives on the same side of the family who developed bowel cancer.
- Cases of bowel and womb cancer on the same side of your family.
- Relatives with multiple (over 10) pre-cancerous growths (polyps) in the bowel.
If any of these apply to your family and you’re worried about your risk of developing bowel cancer, you may want to talk to your . If your GP thinks there’s a chance you may have an increased risk of developing bowel cancer because of your family history, they can refer you to a family history of bowel cancer clinic at West Middlesex University Hospital or elsewhere.
Inherited conditions which increase the risk of bowel cancer
Up to 30 per cent of people will have a close relative with bowel cancer, however, the degree of risk varies between individuals. There are some conditions in which inherited genetic changes greatly increase the risk of bowel cancer developing, such as polyposis and , where many people in a single family can be affected. Only about 5 per cent of bowel cancer cases occur in people who have a very strong inherited predisposition. On the other hand, if only one elderly relative has had bowel cancer, this does not greatly increase your risk.
How can screening reduce my risk of bowel cancer?
The Bowel Cancer Screening Programme (BCSP)
Everyone in England between the ages of 60 and 75 years of age is invited to take part in the National BCSP. This involves 2 yearly stool tests which are sent through the post, the Faecal Occult Blood Test (FOBT). People with an abnormal FOBT test will have a colonoscopy.
During a colonoscopy a long, flexible tube is inserted gently into the back passage to look at the inside of the bowel. Bowel screening aims to detect any precancerous changes to the bowel (known as polyps) that could develop into cancer. These polyps can be removed and cancer prevented. More information about the BCSP can be found at http://www.cancerscreening.nhs.uk/bowel/.
People with a stronger family history
For most people with a family history of bowel cancer the BCSP is an adequate level of screening. For some people with a stronger family history we recommend screening with colonoscopy directly rather than the stool tests. For example this may be from the age of 50 years and every five years for people with 2 close relatives with bowel cancer at a young age. The type of screening for an individual does vary depending on the degree of risk. We can discuss this with you in detail in the family history of bowel cancer clinic and work out what suits you best.
Think you have a strong family history of bowel cancer?
Do you know if anyone in your family has had bowel or any other kind of cancer? Talk to your family and make sure you all know your family history. This would for example be particularly important for those people with a history of bowel cancer diagnosis under age 50 years, or with 2 people in their family affected with bowel cancer.
If you think you have a strong family history of bowel cancer, you should make an appointment with your GP to talk about your concerns. If your GP agrees with you, they can refer you to a specialist family history of bowel cancer clinic at West Middlesex University Hospital. The specialist will go through your family history with you in great detail and ask you to provide accurate information about who has been affected, how old they were when they were diagnosed, and the site where their cancer developed. You may also have to have blood tests as part of this investigation.
You will talk about what types of screening they would recommend, at what age you (and/or other family members) should start being screened and how often you should be screened. Regular screening will ensure that any signs of bowel changes and early cancer are spotted and treated quickly. You can also discuss other ways to reduce your risk through your lifestyle.
Who we are
Dr Kevin J Monahan (Service lead) spent three years working at Cancer Research UK where I completed my PhD in cancer genetics with funding from the Bobby Moore Fund for Bowel Cancer Research. I worked in the Family Cancer Clinic at St Mark’s Hospital in Harrow during this time. I work with Dr Iain Beveridge, Dr Carole Collins, Dr Joel Mawdsley and Dr Krishna Sundaram in the Gastroenterology Department.
Athalie Melville is a Genetic Counsellor from the Kennedy Galton Clinical Genetics Centre in Northwick Park, Harrow. She sepnd time also within the clinic seeing patients before they have genetic testing.
FAP (familial adenomatous polyposis) is a rare genetic disease that causes a family history of cancer and multiple polyps in the bowel.
Lynch Syndrome (also known as hereditary non-polyposis colorectal cancer or HNPCC) is a rare condition that may cause a family history of bowel cancer, and causes 1000 cases of bowel cancer in the UK annually. Anybody diagnosed with bowel cancer under 50 years of age should be tested for this condition (unless they have over 10 polyps)
Information for GPs
Contact detailsThe Family History of Bowel Cancer Clinic, Gastroenterology Department West Middlesex University Hospital, Twickenham Road, Isleworth, London TW7 6AF. Email: firstname.lastname@example.org Telephone: 020 8321 5351 Fax: 020 8321 5024
Useful web pages
- Lynch Syndrome (familyhistorybowelcancer.wordpress.com)
- Lifestyle and Reducing your Risk (familyhistorybowelcancer.wordpress.com)
- Polyposis (familyhistorybowelcancer.wordpress.com)
- Hereditary Colorectal Cancer Syndromes (familyhistorybowelcancer.wordpress.com)
- The Family History of Bowel Cancer Registry (familyhistorybowelcancer.wordpress.com)
- Family history of bowel cancer increases odds of survival (familyhistorybowelcancer.wordpress.com)