Is cancer a hereditary disease?

Is cancer hereditary? This question worries many people who have a family history of cases of oncological diseases. Cancer is a genetic disease and all of 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 the 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 that is not associated with a hereditary mutation.

You are at increased 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 a man;
• “young” cancer in blood relatives under the age of 50;
• a combination of several types of cancer at once in one relative. For example, ovarian and breast cancer.

Hereditary forms of cancer

Common hereditary or “familial” forms of carcinoma include breast, ovarian, lung, and colorectal cancers.

According to a number of studies^[1], a mutation in the BRCA1 and BRCA2 genes is the cause of breast cancer in 10% of women. Approximately one in eight average women in the United States has a lifetime risk of developing this disease – about 12%. Those who have BRCA1/2 mutations have a 72% lifetime risk of the disease.

The BRCA1/BRCA2 genes are involved in the repair of DNA strand breaks and are involved in maintaining the stability of the genome, that is, they control the normal growth of breast and ovarian cells. Violation of their work leads to an increase in errors in the course of DNA repair, which leads to an increased risk of developing cancer of these organs.

Men who have a BRCA2 mutation have a higher risk of developing breast cancer than those who do not. In carriers of the mutation, the risk is about 8% by age 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 occur in lung cancer. This is a common disease in both men and women. 1,7% of lung cancers in people under the age of 68 are hereditary. Harmful factors and an unhealthy lifestyle can trigger the development of the disease. Smoking is an active provoking factor for genetically determined lung cancer. Moreover, the risk is higher, 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 non-polyposis colorectal cancer (HNPCC) 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^[2], these two inherited syndromes account for less than 5% of all cases of colorectal carcinoma.

Non-polyposis colorectal cancer is the most common form of hereditary colon cancer, accounting for about 3% of all colon cancer diagnoses each year. People with HLRCC often have at least three family members and two generations with colorectal cancer, often developing cancer before the age of 50. Not everyone who inherits the HNKRR gene develops colorectal cancer, although the risk is very high, around 80%. People with HNKRC also have a higher risk of developing other cancers (eg, kidney or kidney, ovarian, or 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 thought to be present in about 1% of all people diagnosed with colorectal cancer each year. Polyps occur early in life, with 95% of people with FAP developing polyps by age 35.

Prevention

It is important to assess individual cancer predisposition, especially for family members who have a similar genetic background. The presence of cancer in blood relatives should be the reason for a visit to the doctor, and the study of 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 take a history, conduct a basic examination and develop a plan for additional examination, 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 inclusive, after 40 years – annually.

Also, doctors recommend annually undergoing a complete medical examination of the body – “check-up”. This is an individual diagnostic program, which involves 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 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 of the chest are highly accurate and clarifying methods of examination, therefore, they are prescribed only if the patient has suspicious symptoms or high risk factors.

Significantly reduce the risk of developing cancer, including “family” forms, regular exercise and maintaining a healthy body weight in conjunction with a healthy diet. Doctors also recommend quitting smoking and reducing alcohol consumption. In particular, preventive measures include vaccination and prevention of infectious diseases.

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