BRCA -1 in 400

Has anyone in your family had breast or ovarian cancer? Do you know why some families are more predisposed to develop this disease?

According to the World Cancer Research Fund International, breast cancer represents approximately 25% of cancers in women worldwide; 2%-5% is hereditary due to mutations in the BRCA (BReast CAncer) genes.

BRCA1 & BRCA2 MUTATIONS

We all, regardless of gender, have BRCA1 and BRCA2 genes. Their job is to give instructions for making a protein that act as a tumour suppressor and play a key role in cell division (Roy et al., 2016). In other words, BRCA genes prevent cancer and repair DNA. However, the mutation of any of these two genes means that they cannot perform their job properly and therefore there is a higher risk of developing cancer.

The Royal Marsden NHS Trust states that one in 400 of the population carries a mutated BRCA gene. Although this mutation DOES NOT CAUSE cancer, it increases the risk of developing breast and ovarian cancer and also increases the prevalence of pancreatic and prostate cancer (Pilarski, 2019).

NUMBERS TALK

Being BRCA1 or BRCA2 positive also means that you have 50% probability to pass it down to your offspring. However, this is not always the case; here is my family tree so that you can see real numbers.

My grandma was 1 of 6 siblings, she had 3 brothers and 2 stepsisters. She and one brother were BRCA2+, two brothers and one stepsister were not tested, and the other stepsister is BRCA- however, she has a different mutation (potentially ATM, CHEK2, or PALB2 ) which also increases the risk to develop breast cancer.
If we look now at the first and second generation, we can observe that only one child did not inherit the BRCA2 mutation. This is more than 50%.

It is unknown why some women or men with this BRCA mutation don’t develop the disease. I want to believe that diet and lifestyle plays and important role since the number of women affected by breast and ovarian cancer rises each year faster than the human population growth rate.

PERSONAL EXPERIENCE

My mum is BRCA2+ and had breast cancer at the age of 49. I am BRCA2+ and I have been diagnosed with metastatic breast cancer at the age of 31 despite having done all my check-ups. As mentioned before, there is 85% chance of developing breast cancer during your lifetime if you carry a BRCA2 mutation. I thought I was going to be in the lucky 15% and in case I wasn’t, I would develop cancer later on in my life, around the menopause like the majority of the women in my family.
The reality is that rates of breast cancer increase rapidly in early adulthood, for women with BRCA1 mutation until about age 30 to 40, for BRCA2 until about age 40 to 50 (breastcancer.org). Research by Daly and Antoniou (2017) shows the occurrence of breast cancer by BRCA mutation and age.

If I am totally honest, I have been afraid about having cancer since I knew I had the mutation and the fear and anxiety worsen around the annual screening appointments. For these reasons, I respect those who do not want to know whether they carry the mutated gene. However, if you are aware of it, apart from reducing your own risk, you can avoid passing it on to your child (pre-implantation genetic diagnosis –PGD-) and this is a massive advantage parents have these days.

ACTION PLAN

If breast, ovarian or prostate cancer run in your family you can speak with your GP to request a genetic test. In case you test positive, there are things you can do to prevent the disease:

1. Diet and lifestyle: We are surrounded by junk food, high in sugars and chemicals. Stress, pollution and a sedentary lifestyle also set the perfect scenario for disease to emerge. With the right nutritional, exercise and hygiene advice, we might lower the risk.

2. Oral contraceptives: Taking the combined pill is not advised due to its oestrogen and progestogen content. Although it decreases the risk of ovarian and womb cancer, it doubles the risk of breast and cervical cancer if taken for more than 5 years (Cancer Research UK, n.d.).

3. Chemoprevention: Medications such as tamoxifen, anastrozole and raloxifene, reduce breast cancer incidence in women with a high risk (The Royal Marsden NHS Foundation Trust). Tamoxifen can be given to both pre and post-menopausal women whereas anastrozole and raloxifene only to post-menopausal women. Chemoprevention is suitable for BRCA2 carriers as breast cancers are mainly driven by oestrogen as opposed to BRCA1 carriers.

4. Prophylactic surgery: Preventative surgery that reduces dramatically the risk of developing breast and ovarian cancer. If you want to know more about it, follow Christen Williams, BRCA Chatter on Instagram, Youtube, Facebook or Twitter. She is doing an amazing job at telling her personal experience before, during and after the surgery.

Preventive surgery dramatically reduces the risk of developing breast and ovarian cancer. Prophylactic mastectomy reduces the risk of developing breast cancer by 90-95%. The breast is replaced with implants; nipples are commonly removed. The procedure normally requires 3 days in hospital.
Prophylactic salpingo-oophorectomy when ovaries and fallopian tubes are also removed. This preventive surgery is commonly offered to women who have finished having children. The intervention normally requires only one day in hospital.

5. Breast awareness: While self-exploration does not prevent cancer, you might detect any abnormality earlier. The best time is 3 to 5 days after your period begins.

6. Annual breast screenings: This might include MRI’s, mammogram and/or ultrasound. These screenings do not prevent cancer but could help early detection. I have been doing theses scans since 2016, and had 3 biopsies done. The last biopsy was in April 2019, the consultant told me that if I wasn’t BRCA he wouldn’t have done it, results came back negative.

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SUMMARY

If your family are affected by breast, ovarian or prostate cancer, it might be due to a genetic mutation, most commonly caused by BRCA1 or BRCA2. A genetic test will determine whether you carry it.
Being BRCA+ does not mean you will develop cancer, it means you have a higher risk to develop breast and/or ovarian cancer but it also means that you can be screened more regularly and therefore, have more options to prevent the disease, to avoid passing it on to your child and to catch it at an early stage.

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REFERENCES

1. Cancer Research UK (n.d.). Does the contraceptive pill increase cancer risk? Retrieved from https://www.cancerresearchuk.org/about-cancer/causes-of-cancer/hormones-and-cancer/does-the-contraceptive-pill-increase-cancer-risk
2. Daly, M. & Antoniou, A. (2017). Researchers define cancer risk in BRCA1/BRCA2 carriers. Retrieved from https://www.healio.com/news/hematology-oncology/20170620/researchers-define-cancer-risk-in-brca1brca2-carriers
3. Levy-Lahad, E., Catane, R., Eisenberg, S., Kaufman, B., , G Hornreich, Lishinsky, E. … Shohat, M. (1997). Founder BRCA1 and BRCA2 mutations in Ashkenazi Jews in Israel: frequency and differential penetrance in ovarian cancer and in breast-ovarian cancer families. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1712434/
4. Ovarian Cancer Action, (n.d.). Starting a family. Retrieved from https://ovarian.org.uk/ovarian-cancer/brca/i-have-a-genetic-mutation/starting-family/
5. Pilarski, R. (2019). The Role of BRCA Testing in Hereditary Pancreatic and Prostate Cancer Families. Retrieved from
6. Roy, R., Chun, J. and Powell, S. (2016). BRCA1 and BRCA2: different roles in a common pathway of genome protection. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4972490/
7. The Royal Marsden (n.d.). A beginner’s guide to BRCA1 and BRCA2. Retrieved from https://shared-d7-royalmarsden-publicne-live.s3.amazonaws.com/files_trust/s3fs-public/Beginners_Guide_to_BRCA1_BRCA2.pdf
8. The Royal Marsden (n.d). Chemoprevention for women at an increased risk of familial breast cancer. Retrieved from https://shared-d7-royalmarsden-publicne-live.s3.amazonaws.com/files_trust/s3fs-public/Chemoprevention_women_at_risk_familial_breast_cancer.pdf

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