Breast cancer genetic testing: Impact and advantages

Breast cancer is one of the leading causes of death in Indian women. Around 10-15% of all women have a family history of breast cancer.
In India, breast cancer has the highest incidence and death rate.
In India, breast cancer has the highest incidence and death rate.

KOCHI: Breast cancer is one of the leading causes of death in Indian women. Around 10-15% of all women have a family history of breast cancer. That means having a close relative with breast cancer doubles the risk. Mutations or abnormalities in the BRCA1 and BRCA2 genes are the most common cause of hereditary breast cancer although there are other genes identified. In the Indian population, there is a higher proportion of BRCA1-associated breast cancer (66%) than BRCA2 (45%). Men with a BRCA mutation, especially BRCA2 are also at a higher risk of breast cancer (6-8%).

Both the mutations bring higher risks of breast cancer at a younger age (before menopause). The prevalence of breast cancer gene mutations is higher in Indian patients compared to other populations (20-30%). Also, people who have a mutated BRCA1 or BRCA2 gene have a higher risk of second primary breast cancer. Bilateral breast cancer (cancer in both breasts) is more common in women who carry a BRCA 1 or BRCA2 gene.

These mutations also raise the risk of cancer in ovaries, fallopian tube, peritoneal and pancreatic cancer in women, while men face a higher risk of prostate cancer.

Advantages of genetic testing
That is where genetic testing can help. If the test result is positive, there are steps you can take to lower breast or ovarian cancer risk. Also, the test will help detect these cancers early if they develop. Knowledge is a very powerful tool. This kind of knowledge impacts not only you but your loved ones and the choices they make preventatively and medically.

With an increased risk of breast cancer, frequent and early screenings for both men and women are recommended to catch the disease early. Preventive surgical removal of breasts, ovaries or both to lower cancer risk may be considered Medications are now utilised in cancer patients carrying mutations in the BRCA1 or BRCA2 genes with great success.

Prospective parents may be offered options such as IVF with preimplantation genetic diagnosis to analyze embryos before their transfer to prevent the inheritance of breast cancer genes in their offspring.

Testing and outcomes
A genetic test analyses genes to see if any mutations will increase the risk of cancer. Before testing, consulting a genetic counsellor is essential to select the appropriate test and know what to expect. Genetic testing on a family member who has been diagnosed with breast cancer or ovarian cancer is most meaningful. If you have been tested for a gene mutation, there are two possibilities. If the results are negative, the risk of developing cancer is the same as the general population. If the results are positive, there is a higher risk of cancer. However, not every person in the family inherits it.

Even if a person inherits the gene, it will not always develop into cancer. There is merely an increased risk of cancer. So, consulting with the counsellor again is important. Genetic testing is vital where there is a family history of cancer — selecting which genes to test, when to test and whom to test is required. Genetic counselling is necessary to understand their significance.

The writer is a medical consultant at Metropolis Healthcare Ltd.

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