Prevention

author/s: Dr Dolores Maluenda Colomer, Dr Javier Nebreda Duran, Dr Xavier Llor Farré

 

How can we prevent colorectal cancer?

There are three levels of prevention:

Primary

Primary prevention modifies the causes, making decisions that are the responsibility of Public Health. The objective of primary prevention is to decrease the incidence of colorectal cancer, both in the general population and in risk groups (relatives suffering from the disease, etc.).

Secondary

Secondary prevention allows for an early diagnosis. Its objective is to identify people at greater risk of developing the condition.

It is internationally accepted that prevention of colorectal cancer is performed according to the following guidelines:

    • Patients with no familial history of cancer or polyps of the colon: These patients should have a total colonoscopy every 5-10 years if there have been no findings after the age of 50.

    • Patients with a familial history of first-grade relatives who have suffered from cancer or polyps of the colon: These patients are recommended to have a total colonoscopy after the age of 40 or 15 years before turning the same age the affected relative was when he/she was first diagnosed, and every 5 years if there are no alterations in the first endoscopy.

    • Hereditary syndromes have their own prevention protocols, according to the type of condition. (enlazar con el apartado que trata estos síndromes).


Tertiary

Tertiary prevention refers to the measures that must be taken once a polyp or tumour of the colon has been treated to prevent its recurrence or the development of others. At present, this type of prevention is based on endoscopic examinations and depending on these, it can be divided into:

    • Polyps: Prevention will be carried out based on the size of the removed polyp, as well as on its morphological and histological characteristics. Clearly, a 5 mm polyp is not the same as a 3 cm polyp; as it is not the same if the polyp has a pedicle (that is, like a trunk at the base) of healthy tissue than if it is totally adhered to the wall (sesil polyp), as this latter has a higher risk not to be completely removed, and reproduce again. It is also important the histology (type of tissue which the polyp is composed), as some have a higher risk of malignisation (vellous adenomas…) as compared to other with a lower risk (tubular adenoma, hyperplastic polyp, etc.). Based on all of the above, after a polyp has been surgically excised, the patient should have a new endoscopy done between 6 months and 3 years after the operation. Later on, and if no new polyps are found, this time interval can be spaced out to examinations every 5 years.

    • Cancer: In general terms, tertiary prevention with regard to a person who has undergone surgery for cancer is as follows: During the first 5 years, endoscopies are done every year to prevent possible tumour recurrences and the appearance of new polyps. After that, and if there have been no problems previously, endoscopies are done every 3 years approximately.

 

Frequently asked questions


What methods are available at present in the scope of Public Health to prevent colorectal cancer?

The diet, some drugs and some recommendations prevent colorectal cancer.

Who is in charge of issuing the recommendations referring to the diet?

Different national and international associations are in charge of issuing. recommendations concerning the most appropriate diet to prevent cancer.

The American Society of Cancer, the National Cancer Institute (NCI), the World Health Organisation (WHO) publish very similar recommendations aimed at the population living in industrialised countries.

In Spain, we have the “Clinical Gudelines in Gastroenterology”, Clinical Guidelines in Gastroenterology”, that enjoy the consensus of the Spanish professionals.

Is there a recommended diet to prevent colorectal cancer?

As we know that colorectal cancer has an important genetic component. It is also true to say that there are very significant differences in its incidence, depending on the geographical area of the world. As much higher the economical development of a region is, much incidence of colorectal cancer exists. This fact reflects the importance of environmental factors in the development of this type of cancer, and within these factors, environment will be one of outmost importance. We know that polyunsaturated fats such as olive oil, calcium and vitamind D, can help prevent this type of cancer. And so it is just logical that recommendations should be made with that in mind, especially considering that such diet habits are appropriate to enjoy a good general state of health.

If I have diverticulae, do I have a higher risk of suffering from colorectal cancer?

There is no information sustaining that having diverticulae in the colon is a predisposing factor to develop colorectal cancer.

And if I have ulcerous colitis or Chron´s disease, do I have a higher risk of developing colorectal cancer?

If these diseases affect a limited area of the colon, this risk is similar to that of the general population. If the the condition involves a larger portion of the colon or the entire colon, the risk to have cancer increases, mainly after 8 to 10 years of disease onset. In such cases, a colonoscopy should be done every 1 to 2 years after the disease first appears.

 

Useful advice


What is the most appropriate diet I should follow to prevent colorectal cancer?

You should:

    • Reduce the daily intake of animal fats, favouring the intake of unsaturated fats such as olive oil or fish

    • Include fruits and vegetables in daily meals

    • Keep alcohol intake moderate (1 litre of wine per week)

    • Limit as much as you can the intake of foods conserved in salt or smoked foods

Are there any other recommendations with regard to diet?

Yes.

You should limit how much red meat, processed meat and well done cooked meat or in direct contact with a flame, you eat.

The population at risk should follow a diet rich in milk and other dairy products.

The administration of betakeratins, selenium, A, B, C and E vitamins is not recommended.

The administration of folates supplements is not recommended.

What are the recommendations concerning life style?

    1. Exercise regularly, because exercising helps prevent the development of colorectal cancer.

    2. Avoid tobacco because it predisposes to develop colorectal cancer. This is just another noxious effect that this drug has on health.

    3. Avoid excess body weight and obesity.

Is there any drug that prevents the development of colorectal cancer?

    1. Nonsteroid antinflammatory drugs, among which acetylsalicylic acid (Aspirin) is included, although the generalised used of this medication is not recommended to the side effects it entails.

    2. Postmenopausal hormone therapy is not recommended for prevention

Is there any other information we should know about?

Yes, there is. However, the available information is NOT yet conclusive. There are a number of studies still currently under way, the aim of which is to assess the beneficial effects that can be provided by the use of probiotic and prebiotic compounds.

What is intestinal flora?

The intestine is not just an absorption organ. It is the most relevant element for the activity of the immune system. The immunocompetent cells of the intestine recognise pathogens and activate the production of lymphocytes that, in turn, segregate unspecific antibodies.

Under normal conditions, there is a large variety of microorganism that colonise the last portion of the small and large intestine, constituting the intestinal floral of the human being. Many of these bacteria are beneficial for our body and although other types can be harmful, they live in total harmony in the intestinal lumen.

What causes an alteration of the intestinal flora?

Stress, poor diet habits, or the abuse of antibiotics, are some of the factors that can negatively affect this balance. When this balance is broken, several intestinal disorders can occur as a result. For this reason, it is important to maintain the functions of the bacteria that are beneficial for the intestine.

What are “functional foods”?

Lately, “functional foods” have been gaining more and more popularity. Functional foods are enriched foods that not only provide merely nutritional benefits but also improve general health. This is the case of prebiotic and probiotic compounds that, apart from nourishing, colonise the intestine positively modifying the intestinal flora and improving the functioning of the immune system, and thus, the overall health of the individual.

What is a probiotic compound?

Probiotics are live microorganisms, mainly bacteria and yeast that are added as a diet supplement and that benefit the host, improving the microbial balance of the intestinal flora. In other words, probiotics are live microorganisms that, taken in a certain amount, can provide beneficial effects for the body.

How do probiotics act on the body?

These microorganisms taken in the food reach the small intestine alive where they interact with the bacteria of the endogenous microflora. Moreover, they colonise the large intestine and stabilise the intestinal flora by adhering to the intestinal mucosa to impede the activity of harmful microorganisms. Thus, these lactic acid bacteria also have immunomodulatory properties as much as they stimulate the production of antibodies reinforcing the immune system.

How do they act in colon cancer prevention?

Further rigorous studies are needed to be able to draw specific applications in colon cancer. In general lines, we could say that these bacteria would eliminate unfavourable metalobites and procancerigenous enzymes in the colon.

Is yogurt a probiotic food?

The characteristic that defines a microorganism as probiotic is that it survives the effects of gastric juices and biliary salts, reaching the large intestine alive where it carries out its beneficial function. Many more studies are needed to reach consensus on which foods are probiotics and which are not.

For the time being, the nutritional and contrasted immunomodulatory properties of bacteria (casei, acidophilus, bifidobacteria) have in fact been proven.

What is a prebiotic?

Prebiotics are nondigestable alimentary ingredients of food, to be specific short-chain carbohydrates-that provide beneficial effects to the host, stimulating in a selective way the growth and/or activity of one or of a limited number of bacteria in the colon, improving thereby the general health of the host.

That is, probiotics are substances that are mainly of a vegetal origin and that stimulate the growth and activity of bacterial species, beneficial to the human body.

How do prebiotics act on the body?

Because gastric juices cannot digest them, prebiotics reach the large intestine alive where they enhance the absorption of probiotic foods, improve the functioning of intestinal flora, regulate the functions and increase the number of useful bifidobacteria. Moreover, they also control the absorption of fats on the part of the body during the intestinal transit, acting as antimicrobial and anticancerigenous agents.

How do they work to prevent colon cancer?

When we intake prebiotics (oligosaccharides and inuline), these are transformed by the bacteria of the intestinal flora, fermenting in the colon and producing short-chain fatty acids. These fatty acids are important to maintain the function of intestinal cells, decrease the colonic pH and can prevent the likelihood of developing colon cancer.

Nevertheless, further rigorous studies are needed to draw conclusions as to the true function of probiotics in the prevention of colon cancer.