Is cancer hereditary? This question worries many people, in whose family history there have been cases of cancer. Cancer is a genetic disease and all its forms, without exception, arise as a result of a mutation in the DNA of a cell. Some have a hereditary etiology. But it is important to understand that only a predisposition to certain types of this disease can be transmitted from generation to generation. In such cases, the risk of developing the disease increases, but this does not mean that pathology will necessarily occur. What factors can trigger this mechanism? Who is at risk?
There are two types of DNA changes: germline mutations (changes that are inherited from parents to children) and somatic changes, which are also called acquired mutations. The latter may appear as a result of natural aging or exposure to harmful factors on the body. In general, oncological diseases are now quite common, and the presence of pathology in a blood relative is most likely an accident unrelated to a hereditary mutation.
You are at high risk if:
- there is a fact of family accumulation, that is, three or more cases of the same type of cancer in several blood relatives of the same line;
- the occurrence of carcinoma in first-line relatives (mother, brother, sister) in the absence of external stimuli. For example, the development of breast cancer in men;
- “young” cancer in blood relatives under the age of 50;
- a combination of several types of cancer in one relative at once. For example, ovarian and breast cancer.
Hereditary forms of cancer
Common hereditary or “familial” forms of carcinoma include: breast, ovarian, lung and colorectal cancer.
According to a number of studies, a mutation in the BRCA1 and BRCA2 genes is the cause of breast cancer in 10% of women. About one in eight average women in the United States has a lifetime risk of developing this disease — this is about 12%. In those who have BRCA1/2 mutations, the risk of the disease increases to 72% during life.
The BRCA1/BRCA2 genes are involved in repairing DNA strand breaks and are involved in maintaining genome stability, that is, they control the normal growth of breast and ovarian cells. Disruption of their work leads to an increase in errors during DNA repair, which leads to an increase in the risk of developing cancer of these organs.
Men who have the BRCA2 mutation have a higher risk of developing a malignant tumor of the glandular breast tissue than those who do not have it. In carriers of the mutation, the risk is about 8% by the age of 80, which is about 80 times higher than the average.
Every year, 18 million new cases of oncology of various localization are registered in the world, about two million malignant neoplasms account for lung cancer. This is a common disease in both men and women. 1.7% of lung cancer cases in people under the age of 68 are hereditary. Harmful factors and an incorrect lifestyle can provoke the development of the disease. Smoking acts as an active provoking factor for genetically determined lung cancer. Moreover, the higher the risk, the longer the experience of nicotine addiction, the number of cigarettes smoked per day and the age of the patient. Smokers with a mutation in the BRCA2 gene are almost twice as likely to develop lung cancer.
The two most common hereditary colorectal cancer syndromes are hereditary hereditary nonpolyposis colorectal cancer (HNCP) and familial adenomatous polyposis (FAP). They can affect both men and women who carry these genes. The presence of these diseases increases the likelihood of oncological pathologies up to 50%. According to a number of studies, these two hereditary syndromes are the cause of less than 5% of all cases of colorectal carcinoma.
Non—polypous colorectal cancer is the most common form of hereditary colon cancer, which accounts for about 3% of all diagnoses of the disease of this localization every year. People with HNCP often have at least three family members and two generations with colorectal cancer, often they develop cancer before the age of 50. Not everyone who inherits the HNCP gene develops colorectal cancer, although the risk is very high — about 80%. People with HNCP also have a higher risk of developing other types of cancer (for example, kidney or kidney cancer, ovarian cancer, uterine cancer).
Familial adenomatous polyposis is a rare condition characterized by the presence of more than hundreds or even thousands of benign polyps or neoplasms in the colon and upper respiratory tract. It is believed that it is present in about 1% of all people diagnosed with colorectal cancer every year. Polyps occur at an early age, 95% of people with glanders develop polyps by the age of 35.
It is important to assess individual cancer predisposition, especially for family members who have a similar genetic foundation. The presence of cancer in blood relatives should be the reason for a visit to the doctor, and the study of the medical pedigree can be an important step towards the prevention and early diagnosis of the disease.
In the absence of complaints, it is recommended to contact a specialist once a year. The doctor will collect an anamnesis, conduct a basic examination and develop a follow-up plan, if necessary. A comprehensive check of your health can be done as part of a medical examination. It is held once every three years at the age of 18 to 39 years inclusive, after 40 years — annually.
Also, doctors recommend to undergo a full medical examination of the body annually — “check-up”. This is an individual diagnostic program, which implies an individually selected set of tests and studies for a complete assessment of the state of health. It is important for patients with diagnosed genetic diseases or identified hereditary mutations in genes to undergo regular examinations and be under the supervision of a doctor in order to recognize the problem in a timely manner and apply the necessary treatment.
To prevent cancer of the female reproductive system, it is necessary to undergo a gynecological examination and visit a mammologist, do an X-ray of the chest organs or ultrasound of the breast and pelvic organs. Women under 35 are recommended to visit specialists once a year, after 35 — twice a year. MRI and CT scans of the chest organs are highly accurate and clarifying methods of examinations, therefore they are prescribed only if there are suspicious symptoms in the patient or increased risk factors. Significantly reduce the risk of developing cancer, including “family” forms, regular exercise and maintaining a healthy body weight in combination with a healthy diet.
Doctors also recommend quitting smoking and reducing alcohol consumption. In particular, preventive measures include vaccination and prevention of infectious diseases.