Decoding Hereditary Cancers In women – What Is The HBOC syndrome?

The HBOC syndrome is the hereditary breast-ovarian cancer syndrome which affects usually female members from different generations, in one family. They suffer from breast and/ or ovarian cancer and other tumours as well.

O M, a 38-year-old HR head in a Bank, developed pain in the abdomen and bloating 3 years ago. She was diagnosed with stage 3 ovarian cancer. There was no family history of any cancers on her mother's or father’s side. Following surgery, she went on to receive 6 cycles of chemotherapy. In the meantime, her genetic test reports became available. She had tested positive for the BRCA 2 gene mutation.

Another 32-year-old lady,  A K, a school teacher, presented with a lump in her right breast. It was found to be a triple-negative type of breast cancer. On enquiry, she revealed her maternal aunt and grandmother both had suffered from breast cancer. She received chemotherapy and immunotherapy first to shrink the tumour and then underwent surgery. Genetic testing was performed and she was found to be positive for the BRCA 1 gene mutation.

What is the importance of BRCA genes?

Both BRCA1 and BRCA2 are genes which when mutated (changed or damaged) can cause hereditary breast and/ or ovarian cancer. Hereditary implies that it can be passed on from one generation to the next. Women who harbour these gene mutations are at an increased lifetime risk for breast cancer (about 60 per cent) and ovarian cancer (about 25 per cent) and other cancers such as pancreatic cancers and melanomas. The BRCA 2 gene mutation is also responsible for some male breast cancers.

Does every woman with breast or ovarian cancer need to be tested for BRCA gene mutations?

The simple answer is No. For ovarian cancers, we test all women who have a high-grade serous ovarian cancer type irrespective of age or family history. Almost 20 per cent turn out to be positive. For breast cancer, we test all women under 40 years of age. All women with a type of breast cancer which is called triple-negative breast cancer. And also, women with one or more first-degree relatives with breast or ovarian cancer for e.g. mother, sisters or children. The chances of finding a mutated BRCA gene in these patients are  between 10-15 per cent.

How is this gene tested?

This gene is tested by extracting a blood sample of 3 ml from the patient. The results are usually available after 3-4 weeks. There are several good genetic labs in our country today.

What changes are made to treatment for breast or ovarian cancer if the BRCA gene is positive for a mutation?

For women with ovarian cancer, the treatment of surgery and chemotherapy remains the same. However, there are tablets called Parp Inhibitors which are given for 2-3 years after the chemotherapy, to maintain the remission and prevent the ovarian cancer from coming back. The patient would also be advised 6 monthly screenings for breast cancer as she has a risk of developing it.

For women with breast cancer, the surgery can itself change. A woman with breast cancer and a BRCA mutation can opt for a bilateral breast removal with reconstruction. This risk-reducing surgery brings down the chances of relapse to almost zero. If she has finished childbearing she can undergo removal of the fallopian tubes and ovaries. This will greatly reduce the chances of getting ovarian cancer in the future.

Dr. Shona Nag

Guest Author Director, Oncology Department, Sahyadri Hospitals, Pune