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Research into preventing and diagnosing bowel cancer

Men and women discussing bowel cancer

This page tells you about research into preventing bowel cancer and finding better ways of diagnosing it. You can find the following information

 

A quick guide to what's on this page

Research into preventing and diagnosing bowel cancer

All treatments and tests must be fully researched before they can be adopted as standard for everyone. This is so we can be sure they work better than the methods or treatments we already use. And so that we know they are safe.

Some trials are trying to find out more about what causes bowel cancer. 

There is a lot of research looking into diet, exercise, drugs, and cancer genes to try and prevent bowel cancer, particularly in high risk groups. Using drugs or other agents, such as diet, to help stop a cancer developing is called chemoprevention.

Some trials are trying to find better ways of diagnosing bowel cancer. 

Cancer Research UK supports many of the trials taking place in the UK.

 

CR PDF Icon You can view and print the quick guides for all the pages in the treating bowel cancer section.

 

 

Preventing and diagnosing bowel cancer

All treatments and tests must be fully researched before they can be adopted as standard for everyone. This is so we can be sure they work better than the methods or treatments we already use. And so that we know they are safe.

Some trials are trying to find out more about what causes bowel cancer. 

There is a lot of research looking into diet, exercise, drugs, and cancer genes to try and prevent bowel cancer, particularly in high risk groups. Using drugs or other agents, such as diet, to help stop a cancer developing is called chemoprevention.

Some trials are trying to find better ways of diagnosing bowel cancer. 

Cancer Research UK supports many of the trials taking place in the UK.

 

Understanding the causes of bowel cancer

Researchers are always trying to find out more about what causes different types of cancer. A large study in Scotland is collecting blood and tissue samples from people with bowel cancer. They will study these samples, along with information about how well people respond to treatment, to find out what they can tell us about the causes of bowel cancer.

Researchers are also trying to find out what part stem cells in the bowel wall may play in the development of bowel cancer.

The CORGI study and the PRESENT study are trying to find genes that may increase the risk of bowel tumours. The researchers are looking at the genes of people who have had a bowel tumour. They will also look at their family history to see if any of their relatives have had bowel tumours.

You can find out more about bowel cancer trials on our clinical trials database. Pick 'bowel cancer' from the dropdown menu of cancer types. If you want to see all the trials, tick the boxes for closed trials and trial results. If you use the advanced trials search, you can choose to search for trials looking specifically at prevention or causes of cancer.

 

Inherited risk

One factor that can increase risk of bowel (colorectal) cancer is an inherited faulty gene (gene mutation). This may mean that several people in the same family develop bowel cancer. This is called a strong family history. Inherited conditions such as familial adenomatous polyposis (FAP) or hereditary non polyposis colorectal cancer (HNPCC) also increase the risk.

The level of increase in risk depends on which gene is damaged, or even on which part of the gene is damaged. Some genetic mutations increase risk a lot and are known as high penetrance genes. Others don't increase risk very much and are called low penetrance genes.

A trial called the National study of bowel (colorectal) cancer genetics (NSCCG) aims to find out more about high penetrance genes and how much they increase risk. It is also looking for new low penetrance genes. This trial is listed on our clinical trials database. This research may help doctors to identify people at higher than average risk from bowel cancer. They could then be offered specialist advice and regular screening for early signs of cancer.

 

Preventing bowel cancer

Researchers are looking into preventing bowel cancer using diet, drugs, exercise and weight control. Using drugs or other agents, such as diet, to help stop a cancer developing is called chemoprevention. There is information about preventing bowel cancer below, including

The EPIC study

EPIC stands for the European Prospective Investigation of Cancer. This is an ongoing major study that started in 1992 and involves over 500,000 people in the UK and 8 other European countries. It is looking at the relationship between diet, lifestyle and cancer. It is producing reports on a variety of cancers and will continue for the next 10 to 20 years.

This link for the EPIC study will open its website in a new window, where you can read about its findings.

Diet

We already know that some eating habits can lower the risk of bowel cancer. For example, people who eat more vegetables and less red and processed meat have a lower risk. But we need much more detailed information about this.

Reports from the EPIC study, and a large review of 25 studies reported in 2011, show that eating a diet high in fibre can reduce bowel cancer risk. People who ate the most fibre had a 40% lower risk of bowel cancer than people who ate the least fibre. The EPIC study has also shown that eating fish about 3 times a week may be important in protecting against bowel cancer. 

A pilot study is looking at the effect of helpful chemicals in fruit and vegetables on bowel health in people with pre cancer or cancer of the bowel. Compounds in colourful fruit and vegetables such as tomatoes and berries gather and build up in the bowel. These compounds are called polyphenols. These are broken down by bacteria in the gut into smaller compounds that may protect the gut. Doctors want to understand more about how diet affects bowel health, so they can recommend diets that may prevent cancers of the bowel.

There is detailed information about diet and bowel cancer in our risks and causes of bowel cancer section.

Antioxidants and minerals

Some scientists believe that antioxidant vitamins and minerals may help to prevent cancer when included in a healthy, balanced diet. Vitamin E and the mineral selenium are antioxidants that may play a part in preventing bowel cancer. We don't know for sure whether eating these can help prevent cancer. It is a very difficult thing to prove. But the long term results from the EPIC study may help to answer this question.

Calcium may protect against bowel cancer. A research review found that about 1g of calcium in your diet every day may help to prevent bowel polyps. Polyps are growths in the bowel that may develop into cancer over a long period of time. But the review didn’t find any evidence that calcium in the diet can prevent bowel cancer itself.

Fish oil supplement

The SeAFOod trial is looking to see if a type of fish oil, on its own or in combination with aspirin, can stop small growths on the bowel lining growing back after being removed. There is a risk that these small growths (polyps) may develop into bowel cancer. Doctors know that fish oil can reduce the number and size of bowel polyps in people with a rare inherited condition. Doctors also think that taking daily aspirin helps prevent bowel polyps and bowel cancer, but are not sure yet about the best dose, or who it would help.

Being a normal weight

Reports from the EPIC study show that there is a clear link between being overweight or obese and increased risk of some types of cancer including bowel cancer. Obese means being more than 25% overweight. It is measured by comparing your weight with your height to give your body mass index (BMI). This link will take you to information about how to measure your body mass index

Eating a balanced diet and getting enough exercise can help you to stay at a healthy weight for your height. If you are overweight and finding it difficult to lose weight, it may help to speak to your doctor. They may refer you to a dietician who can give specialist advice on how to lose weight and still have a healthy diet. There is also information about healthy eating on the Cancer Research UK website.

Exercise

Previous studies have linked physical exercise to a lower risk of bowel cancer but not rectal cancer. Results from the EPIC study so far continue to show there is strong evidence that exercise lowers the risk of bowel cancer and breast cancer.

Aspirin and other non steroidal anti inflammatory drugs (NSAIDS)

We know from research that taking regular aspirin or NSAIDs (non steroidal anti inflammatory drugs, such as ibuprofen) may help to prevent bowel cancer and other digestive system cancers. We don't know quite how this works. Most bowel cancers develop from small, non cancerous growths called polyps (adenomas). There is a theory that aspirin or NSAIDs stop an enzyme called COX 2 from working. Blocking this enzyme may help to stop polyps developing.

A research review in 2004 found some evidence that aspirin can reduce the risk of bowel polyps forming. It also found evidence that NSAIDs reduce the size of polyps in people with an inherited disease called FAP (familial adenomatous polyposis). You can read this review of prevention of bowel cancer with aspirin and similar drugs in the Cochrane Library. It was written for researchers and specialists so it is not in plain English.

Studies are going on throughout the world to see if taking these drugs will prevent more polyps forming in people who have already had them removed. These include a number of trials funded by Cancer Research UK. A 2010 review of trials found that taking low dose aspirin for a few years reduced the risk of colon cancer. But aspirin can cause side effects such as bleeding from the stomach lining. Researchers want to find out whether the benefits of aspirin outweigh the side effects. 

A few trials have looked into using a new generation of anti inflammatory drugs called COX-2 inhibitors. One UK trial called Victor was looking at giving rofecoxib (Vioxx) to try to stop bowel cancer coming back after surgery. This and other COX-2 trials were stopped early because there were concerns about side effects and the drugs were withdrawn. In April 2006, two of these trials (called APC and PreSap) reported results for the people who took part before the trials were stopped. Both showed that the drug celecoxib (Celebrex) did lower the risk of pre cancerous polyps coming back. But there were increased risks of heart problems and strokes. Until we know more about how to use this type of drug safely, it won't be sensible to use them to try and prevent pre cancerous bowel polyps.

Remember that aspirin and other NSAID's can be dangerous, especially if you take them on an empty stomach. They can damage the lining of your stomach and cause bleeding. Doctors recommend that people do not take large doses of any of the medicines mentioned here unless they are on a trial that is being closely supervised by a doctor. You certainly shouldn't take aspirin or other NSAIDs regularly without checking with your doctor first.

Statins

Statins are drugs that lower the level of cholesterol in the blood. Cholesterol is a chemical made in the liver from fatty foods that you eat. Because they can lower blood cholesterol, statins are used to try and prevent heart disease and strokes.

Researchers have done case control studies and think that statins may have a role in preventing bowel cancer. But other studies showed either a slight increase or no reduction in cancer for people taking statins. So until placebo controlled trials are done we won’t know whether statins affect the risk of bowel cancer or how they do this.

Curcumin

Curcumin is a substance found in a spice called turmeric. Cultures that use a lot of turmeric in their cooking seem to have fewer cases of bowel cancer. We know from laboratory studies that curcumin may help to stop bowel cancer cells growing. So a small trial has been looking into giving curcumin capsules to people with bowel cancer or bowel polyps. The researchers ultimately want to find out if curcumin can help to prevent bowel cancer developing or coming back. They gave curcumin capsules to people having an examination for bowel polyps or surgery to remove bowel cancer. The aim of this pilot study was to find out how much curcumin is absorbed by the body and whether taking 5 capsules of curcumin a day is safe. The study team found the dose used in this study was safe and that most people would take 5 capsules a day in the long term if proved helpful. Further studies looking into curcumin and preventing bowel cancer are now needed. You can find information about the curcumin study on our clinical trials database.

 

Screening and awareness

In the UK, people are screened for bowel cancer using faecal occult blood testing (FOB). This means looking for hidden (occult) blood in your stool (faeces). You do the test yourself at home with a kit sent to you by post. 

Screening means looking for early signs of a particular disease in people who don't have symptoms. If you are in the age range for the Bowel Cancer Screening Programme, you receive a letter asking if you would like to take part. The letter comes with a booklet about the programme and a kit to collect a tiny sample of stool (faeces). You send the sample back in a hygienic envelope to be tested. The BUCCS study and the ASCEND project are trying to find out why some people don't accept the invitation to take part in the NHS bowel screening programme. Both these studies have closed and we are waiting for the results.

A large UK clinical trial looked into another way of screening healthy people for bowel cancer. Bowel cancers usually develop very slowly from polyps called adenomas. The trial followed more than 170,000 people over 11 years to see who developed bowel cancer. More than 40,000 of those people had a test called flexible sigmoidoscopy between the ages of 55 to 64. Flexible sigmoidoscopy is also called Flexi Scope, flexi sig or bowel scope. It involves having a thin, bendy tube put a short way into the rectum and lower bowel to look at the bowel wall. The doctor or specialist nurse remove any polyps they find.

The study reported in April 2010. The researchers found that those having screening with Flexi Scope reduced their bowel cancer risk by a third, because polyps were removed at an early stage. In England, the Flexi Scope test is now being introduced into the NHS bowel cancer screening programme. This is called bowel scope screening.

We have more detailed information about screening for bowel cancer in the about bowel cancer section.

 

Diagnosing bowel cancer

Doctors are continually looking for better ways of diagnosing bowel cancer. 

Two of the tests doctors use to examine the bowel and diagnose bowel cancer are colonoscopy and barium enema. There is also a new test called CT colonography, also called virtual colonoscopy. This may be particularly good for picking up bowel cancers. And it may be safer and more acceptable for patients. The SIGGAR trial has compared CT colonography (CTC) with normal colonoscopy and barium enema to help diagnose older patients with symptoms. The researchers found that CTC was better at diagnosing bowel cancer and bowel polyps than a barium enema, and missed fewer cancers. But as CTC was better at showing up small polyps, more people went on to have further tests which may not have been necessary, as small polyps are unlikely to become cancerous. The researchers also concluded that CTC was as good as colonoscopy.

The Streamline C study is looking to see if a whole body MRI scan (WB MRI) may be able to replace a range of tests for diagnosing bowel cancer. The aims of the study are to find out if using WB MRI is better or quicker at working out the stage of newly diagnosed bowel cancer than the tests used at the moment. And, to find out the cost of using WB MRI compared to the usual tests.

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Updated: 29 August 2013