Causes and Risk Factors

Colorectal cancer is one of the most common types of cancer in the Western world, while the incidence of this disease is rather low in developing countries. In both males and females, colorectal cancer is the second most common type of cancer; taken together, it is the most common type of cancer in Germany.

Genetic alterations preceding the development of cancer can be caused by outside influences, by an accidental deficiency in cell division or due to hereditary factors. While accidental and hereditary alterations cannot be actively avoided, personal lifestyle may well lower one’s risk to develop colorectal cancer. In order to minimize this risk, screening tests, as well as a healthy lifestyle and diet with the avoidance of potential risk factors, are recommended.

• Diet: A diet with high caloric intake and high in fat, red meats (pork, beef, lamb, venison), smoked, cured or processed meats, sausages and sugar on the one hand and very low intake of vegetables, fruits and fibers on the other hand, increases the risk of developing colorectal cancer. Vegetables and fruits, fish, eggs and poultry, vegetable oils, milk and milk products, whole meal products, nuts and legumes should be a regular part of a balanced diet. 
   ⇒ Here you can find more information about a healthful and balanced diet: Felix Burda Stiftung, Deutsche Gesellschaft für Ernährung and Gesellschaft für Biologische Krebsabwehr e.V. (GfBK e.V.).

• Overweight is the consequence of constant overeating and lack of exercise, and is considered as one of the greatest risk factors for colorectal cancer and many other diseases and types of cancer.

• Lack of Exercise: Constant exercise helps to lower the risk for many diseases including colorectal cancer. It is sufficient to integrate physical activity into daily life - according to scientific studies, exercizing 30 to 60 minutes a day helps to lower the risk for colorectal cancer.

• Smoking. Most people know that smoking increases the risk for heart attack and lung cancer, but it does also increase the risk for colorectal cancer.

• Alcohol: It is proven that alcohol has a negative influence on the risk of colorectal cancer.

• Genetic Risk (Family Syndrome) / Family History
  
  Hereditary Colorectal Cancer: These are very rare types of colorectal cancer (e.g. FAP and HNPCC) and largely occur due to genetic alterations that are known and detectable. The persons concerned are usually young of age.
  
  Family History: A family history of colorectal cancer can apply even without a known hereditary colorectal cancer. It is hard to identify the causes since it remains uncertain whether the increased risk originates from a common genetic pool or a common lifestyle. However, it is very important to perform screening tests within the affected families.
  
  Web links for hereditary colorectal cancer:
  »Deutsche Krebshilfe - Zentren für familiären Darmkrebs
  »Joint project „Familiärer Darmkrebs“
  »Search function for centers for human genetic counseling in your vicinity

• A History of Inflammatory Bowel Disease is one the proven risk factors for colorectal cancer.
  
  Ulcerative Colitis is considered a serious risk factor for colorectal cancer. The degree of the risk depends on the age at which the first symptoms occured as well as on the degree of the inflammation.
  
  Crohn’s Disease seems to increase the risk for colorectal cancer, even though this cannot be currently confirmed due to contradictory study results.

• Type 2 Diabetes: People with type 2 diabetes have a three times higher chance of developing colorectal cancer.

• Age over 50: The chances of developing colorectal cancer increase after age 50. At the latest at the age of 50 men and women are strongly recommended to attend screening tests.

• Vitamin pills and dietary supplements are not recommended and may even cause adverse effects. A balanced diet is definitely preferable to the intake of vitamins, minerals and micronutrients.