Lynch syndrome (HNPCC)
Colon cancer is a malignant tumor of the colon (large intestine). A tumor develops because one of the cells in our body starts to grow in an uncontrolled manner. Tumors can be benign or malignant. A benign tumor grows by pushing surrounding tissue aside without causing much damage, whereas a malignant tumor (
Hereditary Colorectal Cancer (Lynch Syndrome)
About 3 to 5% of patients with colorectal cancer have a hereditary form known as Lynch syndrome. Hereditary colorectal cancer is usually diagnosed at a younger age (often below the age of 60) and differs in several other ways from the non-hereditary form. Most hereditary colorectal cancers occur on the right side of the large intestine, i.e. in the ascending or transverse part of the colon. Another feature of hereditary tumors is that, following a first colon cancer, a patient has an increased chance of developing a second colon tumor. A final characteristic is that family members in some families with hereditary colon cancer may develop cancer of the uterus and other tumors.
A polyp or a malignant tumor in the colon does not always cause symptoms. If a complaint occurs, the sort of complaint depends on the location of the tumor.
The following symptoms may occur when a polyp or a malignant tumor is located in the last part of the intestine:
- changes in stool pattern
- diarrhea or alternating constipation and diarrhea
- urgency but without feces
- blood or mucus in the stool
If a large polyp or malignant tumor has developed in the first section of the colon, the following symptoms may occur:
- anemia due to chronic blood loss in the colon
- a vague abdominal pain
- a swelling in the abdominal area
It is important to realize that these symptoms do not always mean that a polyp or tumor is present! This type of complaint can also have other causes, such as a low-fiber diet or nervousness. A hemorrhoid is a common cause of blood and/or mucus in the stool. However, it is important that you consult your GP or specialist if your symptoms persist for more than three weeks.
The body is made up of cells, each of which has a nucleus containing 23 pairs of chromosomes, thus 46 in total. Chromosomes contain tightly packed DNA, parts of which act as genes, the DNA ‘blueprints’ for a hereditary trait. For each of your 23 pairs of chromosomes, one came from your mother and the other from your father, and which chromosome from each pair is inherited is entirely random. From mother and father combined, a child thus receives 46 chromosomes. In hereditary colorectal cancer, predisposition to disease is passed to offspring by a parent. Children, both boys
The question of whether a hereditary form of colorectal cancer occurs in a family can be partly answered by a family study. This investigation involves drawing a family tree that contains medical data from family members. When colon cancer is diagnosed in three or more close relatives, and the disease was diagnosed in at least one person at an age younger than 50 years, a diagnosis of hereditary colorectal cancer is likely. In some families that meet these
Preventive measures for the carriers of one of the gene defect causing Lynch Syndrome
When discovered, polyps are removed during a colonoscopy. Most polyps prove to be benign lesions. However, if a malignant tumor is diagnosed, an operation to remove the section of intestine close to the tumor (bowel resection) becomes necessary. In hereditary colon cancer, new polyps and malignant tumors may sometimes develop in the remaining part of the intestine. Removal of the entire colon (total colectomy) is therefore preferred in young patients. During this operation, the last part of the small intestine (the ileum) will be connected to the rectum (the rectum), a surgical technique known as colectomy with ileorectal anastomosis.
Preventive measures on uterine cancer
Uterine cancer may also occur in some families with Lynch syndrome. It is therefore advisable that women in these families participate in uterine cancer screening once every 1 to 2 years, from the age of 40. This preventive examination usually consists of a physical examination by a gynecologist, and a transvaginal ultrasound, a technique that uses sound waves, via the vagina, to create an image of the uterus and ovaries.