How to prevent colorectal cancer?

The exact cause of colorectal cancer is unknown in most patients. However, there are some risk factors known to increase the risk of developing colorectal cancer. The risk of developing this potentially fatal tumour can be decreased by both primary and secondary prevention.

Primary prevention

Primary prevention of cancer is aimed at the reduction in incidence rate of malignant tumours. This consists in the reduction or even elimination of risk factors which have a demonstrable and direct impact on the development of malignant tumours.

Adherence to the following recommendations contributes not only to colorectal cancer prevention, but other types of cancer as well. These recommendations are based on the findings of the WCRF/AICR report from 2007, entitled Food, Nutrition, Physical Activity, and the Prevention of Cancer: a Global Perspective [1].

If you want to lower your risk of developing cancer, you should adhere to the following rules:

	Be as lean as possible without becoming underweight. Convincing evidence shows that weight gain and obesity increases the risk of a number of cancers, including bowel and breast cancer. Maintain a healthy weight through a balanced diet and regular physical activity to help keep your risk lower.
	Be physically active for at least 30 minutes every day. There is strong evidence that physical activity protects against cancers including bowel and breast cancer. Being physically active is also key to maintaining a healthy weight. Any type of activity counts – the more you do the better! Try to build some into your everyday life.
	Limit consumption of energy-dense foods (foods high in fats and/or added sugars and/or low in fibre) and avoid sugary drinks. Energy-dense foods are high in fats sugars and can be low in nutrients. These foods, especially when consumed frequently or in large portions, increase the risk of obesity, which increases the risk of cancer. Fast foods like burgers, chips, fried chicken and most pizzas, and snack foods like chocolate, crisps and biscuits tend to be energy dense. Some energy-dense foods, such as nuts, seeds and some vegetable oils are important sources of nutrients, and have not been linked with weight gain as part of a typical diet.
	Eat more of a variety of vegetables, fruits, wholegrains, and pulses such as beans. Evidence shows that vegetables, fruits and other foods containing dietary fibre (such as wholegrains and pulses) may protect against a range of cancers including mouth, stomach and bowel cancer. They also help to protect against weight gain and obesity. As well as eating your 5 A DAY, try to include wholegrains (e.g. brown rice, wholemeal bread and pasta) and/or pulses with every meal. Sugary drinks, such as colas and fruit squashes can also contribute to weight gain. Fruit juices, even without added sugar, are likely to have a similar effect, so try not to drink them in large quantities. Try to eat lower energy-dense foods such as vegetables, fruits and wholegrains instead. Opt for water or unsweetened tea or coffee in place of sugary drinks.
	Limit consumption of red meats (such as beef, pork and lamb) and avoid processed meats. There is strong evidence that red and processed meats are causes of bowel cancer, and that there is no amount of processed meat that can be confidently shown not to increase risk. Aim to limit intake of red meat to less than 500g cooked weight (about 700-750g raw weight) a week. Try to avoid processed meats such as bacon, ham, salami, corned beef and some sausages.
	If consumed at all, limit alcoholic drinks to 2 for men and 1 for women a day. Since the 1997 report, the evidence that alcoholic drinks can increase the risk of a number of cancers, including breast and colon cancer, is much stronger. Any alcohol consumption can increase your risk of cancer, though there is some evidence to suggest that small amounts of alcohol can help protect against heart disease. Therefore, if you choose to drink, do so in moderation.
	Limit consumption of salty foods and foods processed with salt (sodium). Evidence shows that salt and salt-preserved foods probably cause stomach cancer. Try to use herbs and spices to flavour your food and remember that processed foods, including bread and breakfast cereals, can contain large amounts of salt.
	Don’t use supplements to protect against cancer. Research shows that high-dose nutrient supplements can affect our risk of cancer, so it's best to opt for a balanced diet without supplements. However, supplements are advisable for some groups of people (if you have any doubts, ask your doctor).
	It is best for mothers to breastfeed exclusively for up to 6 months and then add other liquids and foods. Strong evidence shows that breastfeeding protects mothers against breast cancer and babies from excess weight gain.
	After treatment, cancer survivors should follow the recommendations for cancer prevention. Maintaining a healthy weight through diet and physical activity may help to reduce the risk of cancer recurrence.

Secondary prevention

Secondary prevention of cancer is aimed at the detection of malignant tumours at early, completely curable stages. In case of colorectal cancer, secondary prevention consists in colorectal cancer screening, which can be summarised in a few general recommendations.

• You can also try our interactive guide to colorectal cancer screening, which will help to choose the most appropriate screening method for you.

Reference

1. World Cancer Research Fund / American Institute for Cancer Research. Food, Nutrition, Physical Activity, and the Prevention of Cancer: a Global Perspective. Washington DC: AICR, 2007. Available from WWW: http://www.dietandcancerreport.org/cancer_resource_center/downloads/Second_Expert_Report_full.pdf

Last updated on 12 January 2015