Introduction
Colon cancer is one of the most common cancers in adults. On the one hand, it poses a great danger, but on the other hand, the screening programmes and treatment options for this disease are promising. Most people are diagnosed with colorectal cancer at an advanced age.
It is not unusual for it to be in an advanced stage at this time. However, a small proportion of colorectal cancers can be traced back to hereditary genetic defects or family history. In these cases, an earlier age of onset of the disease is to be expected, so that preventive examinations should also be started earlier.
Hereditary diseases with higher risk of colon cancer
When talking about hereditary cancer, a distinction must be made between clear genetic defects and family predisposition. The latter is only associated with a slightly increased risk of colon cancer and does not necessarily have to be genetic. Individual risk factors such as obesity and smoking may also be responsible for part of the family clustering. Actual inheritance is referred to in the case of gene mutations such as Lynch syndrome or familial adenomatous polyposis. With these syndromes there is an enormously high risk of developing intestinal cancer during the course of life.
This percentage is inherited
The gene mutations that can cause colon cancer are comparatively rare. Even if the rate of colon cancer is enormously high for one of the genetic diseases, only a maximum of 5% of all colon cancers are due to such a syndrome. About 70% of the patients develop intestinal cancer.
However, other types of cancer can also occur as a result of hereditary syndromes. In up to 50% of cases, cancer of the uterus occurs, and more rarely stomach or ovarian cancer. With the FAP syndrome, which is associated with several polyps of the large intestine, there is even an almost 100% risk of intestinal cancer. Sooner or later, all those affected would develop malignant tumours from the numerous polyps if left untreated.
With these types of tumors I also have a risk of colon cancer
The so-called polyps play an important role in the development of colon cancer. They are also known as adenomas and initially represent benign growths of the intestinal mucosa. The fast-growing mucous membrane ulcers can change in the short or long term and grow into malignant cancers. Gene defects can also lead to the growth of polyps in hereditary tumour syndromes. The so-called FAP syndrome is accompanied by the fact that numerous benign tumours grow at a young age, so that the risk of developing malignant cancer at a later stage is almost 100%.
How can I determine if I have a genetic risk of colon cancer?
It is extremely important to discover a potential genetic defect at a young age, which is associated with high risks of hereditary colorectal cancer. If one parent is already affected by an inherited tumour syndrome, there is an approximately 50% probability that the child has inherited the syndrome. If such a suspicion exists, a genetic examination as well as comprehensive counselling of the affected person and the whole family is urgently required.
Such a genetic test can be performed voluntarily. Nowadays, many causal syndromes can already be diagnosed, but if the results are negative, a residual risk of an unidentified syndrome remains. Especially if one parent is already affected, regular testing should be carried out at large intervals.
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