Causes

20-30% of colorectal carcinomas occur more frequently in families. This means that a person who has a first-degree relative (especially parents) with colorectal cancer has a 2-3 times higher risk of developing colorectal cancer in the course of their life. In addition, some lifestyle factors play an important role.

Especially overweight persons (BMI >25) who do not exercise regularly, smoke cigarettes and drink a lot of alcohol have an increased risk of developing colorectal cancer. In addition, a low-fiber, high-fat diet and a high consumption of red meat also have a negative effect. Most colorectal carcinomas occur after the age of 50.

The risk of developing such a disease increases with age. People who suffer from a chronic inflammatory bowel disease also have an increased risk of developing colorectal cancer. If there are several cases of the disease in the family and the patients were remarkably young at the time of diagnosis, it is reasonable to think of a genetic cause of colorectal cancer.

Genetic causes include Lynch syndrome, also known as HNPCC (=hereditary non-polyposis colorectal cancer), FAP (Familial Adenomatous Polyposis Coli) or MAP (MYH associated polyposis). Patients with such genetic cancers are recommended to undergo more thorough screening to detect and treat malignant changes in time. Colorectal carcinoma is ideally detected in the course of a preventive examination.

This is recommended in Germany from the age of 50. Usually a colonoscopy is performed. This offers the possibility of directly recognizing abnormalities in the intestine, removing them and subsequently examining the tissue.

If the examination remains without conspicuous findings, a control examination is recommended in 10 years. Alternatively, the patient can be offered an annual examination of the stool for blood not visible to the naked eye (=occult). If the result is positive, a colonoscopy is also necessary for further clarification.

If the examination of the removed tissue reveals that the tumor is malignant, a number of additional diagnostic measures are initiated to determine the spread of the tumor as accurately as possible. In addition to a complete colonoscopy, these include an ultrasound examination of the abdomen and an X-ray examination of the chest. A CT or MRT examination is also performed. To assess the height of the tumor, an examination with a rigid device, a rectoscope, is performed in the case of rectal cancer. In addition, a blood test is carried out, in which, among other things, the tumor marker CEA is determined to monitor the course of the disease.