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Some families are more affected by cancer than others. And yet, it can be said: "Cancer is not hereditary," says Dr. Malin Dewenter, University Medical Center of Mainz. "Most cancers are multifactorial." This means that the development of cancer is the result of the interaction of environmental factors and several genetic plants. In principle, 5 to 10% of malignancies (malignant tissue regeneration) can be attributed to familial hereditary factors. "In these cases, a genetic predisposition can usually be pbaded from generation to generation with a 50% probability," says the doctor. This applies i. d. A. Only for selected part of cancers such as hereditary bad and ovarian cancer, predisposition to colon cancer or, in rare cases, hereditary gastric cancer.
In the case of bad and ovarian cancer, the most common cause of the disease is a gene mutation of the BRCA1 or BRCA2 gene (BRCA = BReast CAncer)
A distinction is made between syndromes Hereditary colon cancer and HNPCC syndrome (non-polyposed hereditary colorectal cancer, MLH1, MSH2, MSH6 and PMS2 genes) and FAP (familial adenomatous polyposis, APC gene or attenuated FAP gene, MUTYH gene).
HNPCC syndrome, also known as Lynch syndrome, is a hereditary predisposition to colon cancer (lifetime risk of about 80%), but also to other carcinomas such as cancer of the colon. Stomach and intestines. and carcinomas of the bile ducts.
FAP is characterized by the development of numerous intestinal polyps, called colorectal adenomas (at least 100, often more than 1000). These are initially mild but may progress to malignant colon tumors (carcinomas) over the years. In addition, other organs and organ systems may have changes in addition to the intestine, z. B. benign changes to the bone. Patients also increase the risk of certain other malignant diseases (semi-woody desmoid, papillary carcinoma of the thyroid, medulloblastoma, sarcoma or hepatoblastoma).
The risk of contracting endometrial cancer (uterine cervix cancer) may also increase Have a predisposition to a form of colon cancer or hereditary bad cancer and the risk of endometrial cancer. ;ovary. Especially in the case of HNPCC syndrome, the risk for this type of tumor is significantly increased in affected women (40-60% lifetime risk). Endometrial carcinomas, however, are also more common in carriers of a BRCA1 gene mutation as well as in those affected by less common tumor syndromes (eg, Peutz-Jeghers or Cowden syndrome). )
"Is cancer the result of hereditary predispositions? if you do not look at it first, "says Prof. Dr. med. Stefan Aretz, University Hospital Bonn, to consider. Only certain abnormalities in cancer history in the patient's or family's history suggest that they could be hereditary tumors, which may also be badociated with an increased risk of cancer in family members still in the family. healthy. It is therefore important to identify families with a hereditary propensity to offer carers intensive screening and screening for cancer (possibly for preventive surgery).
"It is particularly noticeable when a cancer buildup in a family occurs. This accumulation should not always refer to a type of tumor. Even if a person from a family falls ill from a young cancer – well under 50 – or in life, the same type or a different type of cancer occurs multiple times independently, one should think to a hereditary form, "explains Professor Aretz. Basically, the various hereditary tumor syndromes are badociated with the onset of certain types of tumors and so there are specific criteria that determine when a genetic diagnosis should be made. Human genetic diagnostic laboratories are responsible for this diagnosis. Families who detect an accumulation of cancer can go to a human genetics institute for advice. The advice there is an advantage of health insurance and therefore possible for free. In addition, there are specialized centers for the detection and treatment of hereditary cancers. In the case of bad and ovarian cancer, it is z. B. German Consortium for Breast and Ovarian Cancer.
In order to determine whether a healthy person has a hereditary cancer predisposition, a genetic test should be performed on an already ill person in the family in order to diagnose hereditary inheritance in the family and responsible for carcinogenicity (mutation). This inquiry is made i. d. R. on a blood test. Context of this procedure: Without examination of a sick family member, doctors do not know at all if they can find a causal mutation in the family. "If a person is diagnosed with a mutation, a clear diagnosis can be made and all other (still) healthy people in the family who have an increased risk of cancer can then undergo a genetic test," says Professor Aretz. If the family transfer can be ruled out, parents and their offspring are no longer at risk of developing a disease and are therefore mentally relieved.
If no cancer-causing mutation is found, it may mean that there is no hereditary predisposition to cancer. East. "But it is also possible that it is a mutation that can not (yet) find the drug with the techniques at its disposal, or that it is the genetic mutation that we have not yet known," says the doctor. to consider. In these cases, it is possible to clinically evaluate the risk for other family members, particularly on the age of onset and the spectrum and accumulation of tumors in the family. "But even the clinical criteria are not perfect," says Professor Aretz. Many families with a hereditary cancer predisposition are still not recognized. at. Indeed, medical attention in everyday life is not always sufficient or medical information about sick family members can no longer be obtained. "There is still room for improvement here," he says. "It's always good that patients themselves are sensitized."
Prophylactic measures against hereditary cancer
If there is a FAP, there is an almost 100% chance of developing colon cancer over the course of life. Prophylactic ablation of the colon is therefore recommended in case of adenomas. The optimal time for surgery depends on the number and size of the polyps and should be determined with the patient. Regular follow-up is necessary after surgery because polyps and cancer can also occur in the stomach, small intestine or rectal stump.
HNPCC carriers are advised not to use prophylactic exudation, but to use an intensive screening program. :
- Annual colonoscopy (from the age of 25 or 5 years before the onset of age)
- Annual transbadl ultrasounds (from 25 years)
- Annual endometrial biopsies ( from 35 years)
- from the stomach and duodenum (from 35 years)
In addition, it is recommended to do a physical examination and an ultrasound of the abdomen once per year. In addition, patients aged 40 and 5 years before the onset of the family should be offered an interview on the removal of the uterus and possibly ovaries.
Caregivers of a BRCA1 or BRCA2 gene mutation Women with a calculated probability of more than 20% for mutation detection or lifetime bad cancer risk of more than 30% are recommended to intensify bad cancer screening. This includes the following exams:
- Breast Medical Palpation Semi-Annual
- Breast Ultrasound Examination
- MRI Breast Examination Once a Year
- Mammography, Optionally From the Age of 40 (Individual Decision) [19659018] In addition With the gynecologist, regular badl ultrasound examinations of the ovaries (twice a year) may be considered. In addition, it is possible to remove the bad tissue (possibly with a structure) and after the completion of the child's planning, the removal of the ovaries is recommended.
Is my family a cancerous family?
A genetic test is: i. d. R., if the badumed risk of detecting a gene change is greater than 10%. There are special prediction programs for this. These are based on the following criteria for genetic testing for the presence of changes in the BRCA1 or BRCA2 gene developed (each in a family line):
- 1 case of bad cancer before the 36th year
- 2 cases of bad cancer, including at least 1 case before the age of 51
- 3 cases of bad cancer
- 1 case of bad cancer and 1 case of ovarian cancer
- 2 cases of ovarian cancer
- 1 case of male bad cancer
In addition, it is currently discussed whether genetic testing should also be recommended in isolated cases of specific bad cancer (triple negative tumor biology, TNBC) or ovarian cancer (high quality serology).
Source: Life? Live!
7.4.18
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