Hereditary breast and ovarian cancer syndrome

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Article by Dr. Hoang Quoc Chinh - Medical Genetics Division, Vinmec High-Tech Center
Hereditary Breast and Ovarian Cancer (HBOC) is a syndrome that increases the risk of certain types of cancer and begins at a younger age than the population average. HBOC carriers have an increased risk of breast, ovarian, and certain other cancers.

1. Causes of HBOC . syndrome

HBOC syndrome is caused by the inactivation (mutation) of genes involved in repairing damage to the genome. When these genes are mutated, the ability of the genome to repair abnormalities is completely or partially lost, thereby leading to the accumulation of mutations in the cell. If, unfortunately, these mutations occur in genes that cause cancer, the cells carrying the mutation will be converted into cancer cells. Cancer cells continuously grow, develop and form tumors.

HBOC syndrome is an inherited disease caused by a genetic mutation. This means that factors that increase the risk of cancer are passed down from generation to generation in a family. Mutations in the BRCA1 and BRCA2 genes are the most common cause of HBOC syndrome. Females with mutations in the BRCA1 and BRCA2 genes have a higher risk of developing breast and ovarian cancer than the general population. Men with mutations in these two genes also have an increased risk of breast and prostate cancer. Mutations in these two genes also slightly increase the risk of other cancers. Diseases adjacent to BRCA1 and BRCA2, mutations in other genes such as TP53, PTEN, CDH1, ATM, CHEK2, or PALB2 are also responsible for this syndrome.

Approximately 1% of the population carries a mutation in the BRAC1/2 gene, and about 10% of female breast cancer patients and 20% of male breast cancer patients carry an inherited mutation in the BRCA1/2 gene. Approximately 30% of female breast cancer patients are diagnosed younger than 60 years of age and have a negative triplet that carries genetic mutations in the BRCA1 and BRCA2 genes. Therefore, these patients are often advised to have genetic counseling and genetic testing. HBOC syndrome is often found in families with multiple breast and/or ovarian cancers. If a family has four breast cancer patients diagnosed at the age of less than 60 years, the family member's risk of HBOC is 80%, while this figure is only about 10% if the family has one patient. female breast cancer patients are diagnosed at the age of less than 50 years.
HBOC syndrome has no characteristic appearance, thus cannot be detected through routine physician examination. The diagnosis of hereditary breast and ovarian cancer syndrome is made only through analysis of the genes involved in this syndrome.

2. Who should perform the test?

Each person's cell has two copies of a gene; One copy is inherited from the father and the other copy is inherited from the mother. HBOC syndrome is a dominantly inherited syndrome, meaning that just one copy of the faulty gene is enough to cause the syndrome. During fertilization, the zygote (the mother cell of an organism) can receive a faulty copy or a normal copy from either parent if either parent is a carrier of the genetic mutation. This means that the father, mother, brother, sister, and biological child of a carrier of the genetic mutation have a 50% chance of carrying the same type of mutation (Figure 3).

Hereditary breast and ovarian cancer syndromes are usually found in people with one of the following manifestations. However, these criteria only detect about 50% of people with HBOC syndrome.
In the family there is a carrier of genetic mutations in genes that increase the risk of cancer Patients with breast cancer diagnosed aged 45 years or younger Patients with breast cancer, and a family history of the disease cancer Patients with breast cancer with a “triple negative” and diagnosed at age 60 or younger. Cancer in both breasts or ovaries. Patients with ovarian cancer, male breast cancer, metastatic pancreatic or prostate cancer. The BRCA1/2 gene mutation was detected in the tumor.

3. Methods to reduce risk

Preventive surgery.
Surgery to remove both breasts can reduce the risk of breast cancer by up to 90%. Only about 3% of breast cancer patients with an inherited mutation in the BRCA1 or BRCA2 gene are diagnosed before age 30, so women with an inherited mutation in the BRCA1 or BRCA2 gene may consider surgery after age 30.
Removal of the ovaries and fallopian tubes can reduce the risk of ovarian cancer by 90 and the risk of breast cancer by 50%.
Since containment surgery is an invasive and irreversible procedure, the decision to perform containment surgery should be carefully considered. Doctors and genetic counselors can provide information about the benefits and risks based on your health, type of mutation, and family history, but cannot make decisions for you.
Drugs reduce the risk.
Certain drugs can help reduce the risk of cancer. Example: Women at high risk who take Tamoxifen for 5 years can reduce their risk of breast cancer by 50%. Similarly, raloxifene (Evista) and aromatase inhibitors (AIs) may also reduce the risk of breast cancer in high-risk individuals. However, the risk-reducing effect of these drugs in gene mutation carriers has not been elucidated.
Taking birth control pills for 5 years can reduce the risk of ovarian cancer by 50% for BRCA1 or BRCA2 gene mutations.
Maintain a healthy lifestyle.
Practicing a healthy lifestyle, including “eating right, getting enough sleep, exercising regularly, staying away from stress and stimulants, and maintaining BMI < 23 kg/m2), is an effective way to reduce risk most effective and effective not only for cancer but also for most chronic diseases.
Currently, Vinmec International General Hospital is the first medical facility in Vietnam capable of implementing cancer screening by combining 4 technologies: genetic testing, endoscopy, ultrasound and laboratory testing. immunity. In which, cancer screening with gene technology is a method that is considered a breakthrough in medicine.
Early screening is considered the "golden key" to detect and provide prevention methods, reduce the risk of death and costs for patients. Due to late detection (70% of patients are treated when they are at the end stage), the death rate from cancer in Vietnam is very high. To register for examination and treatment at Vinmec International General Hospital, you can contact the nationwide Vinmec Health System Hotline, or register online HERE.