Most cancers that are diagnosed in people are not hereditary. This means that the main cause for the cancer is not a genetic mutation that is transmitted or transferred from parent to child. Cancers develop because of genetic mutations that develop due to other causes (spontaneous) but not due to transfer from parent to child. In all, about 5% of all cancers are said to have a significant genetic link.

Hereditary Breast and Ovarian cancer

Most women who develop breast and ovarian cancer do not have a hereditary link. Generally, about 5%-10% of cancers can have this link, but it is felt this figure is higher in the Indian population. Most hereditary breast and ovarian cancers are due to mutations present in BRCA1 and BRCA2 genes. Other mutations such as TP53 and PALB2 account for a few. Patients or families who have BRCA1 and BRCA2 mutations have an increased risk of breast and ovarian cancer as well as breast cancer in males in the family, prostate cancer and pancreatic cancer.

In the general population (those without cancer), the risk of having BRCA 1 and BRCA2 mutations is small but those patients having found to have mutations in these genes have a high risk of getting a cancer. For example, in a patient with such a mutation, there is a 70% risk of breast cancer in their lifetime and a 20%-40% risk of developing ovarian cancer in their lifetime. In males with this mutation, there is a 7%-8% risk of breast cancer.

Who should be tested for this condition?

There are many guidelines used to determine people who should be considered for testing for BRCA1 and BRCA2 mutations. These can include people with a history of breast cancer or ovarian cancer in them or a close relative aged less than 45-50 years of age, multiple relatives with breast cancer, close family history of male breast cancer, prostate or pancreatic cancer.

How is it tested?

Testing is done by either using a blood sample or a swab taken from the mouth and sent for multi gene panel testing (NGS).

What to do if result positive for BRCA?

The following is advised for people or patients who have tested positive for a cancer-causing mutation in BRCA1 or BRCA2 gene.

Lifestyle modification includes stopping smoking, consideration of not suing contraceptive pill, use of breast feeding as this can reduce the risk of both breast and ovarian cancer.

For women with no history of breast cancer and have been found to be BRCA positive, removal of both breasts and ovaries significantly reduces the risk of getting these cancers. It does not however eliminate the risk fully. There are side effects of having such surgery as removal of ovaries creates a menopause which in turn causes symptoms. This option of risk reducing surgery should be discussed with the treating doctor in detail, assess the pros and cons of such a move before the decision. This surgery is contemplated after completion of family (had children).

The alternative to risk reducing surgery is effective regular screening tests for both the cancers. For people who do not have surgery, screening for breast cancer is started early from the age of 25. At that age, MRI scan of the breast every year is recommended over other tests. Ovarian cancer screening is done with an ultrasound scan (trans vaginal) and blood test, CA125, every 6 months from the age of 30.

If a BRCA positive person wishes to have children, there is a 50% chance that each child will inherit the BRCA gene. This has to be considered before that decision is made.