Start the conversation about Breast Cancer risk - geneType
Start the conversation about Breast Cancer risk
Published Mar 2, 2022

It’s time to start a conversation about breast cancer risk

Under the fluorescent lights of a doctor’s office, it’s not always easy to know what questions to ask. While breast cancer can be an awkward topic, knowing your risk is important 1-3 – so here are some questions about breast cancer risk that you might want to ask your doctor at your next visit.

Can I control my risk of getting breast cancer?

Risk factors for breast cancer are often things that we can’t change like our genetics or family history,1 but our lifestyle choices (like smoking and drinking alcohol) also play a role.1 Even if you can’t completely control your risk for breast cancer, knowing your risk means that you can work with your doctor to put in place a personalised breast health plan. This might include reducing risk options that are focused on lifestyle modifications, or more serious risk reducing options including medications and additional types of or more frequent screening.2,3

Should I be tested for a BRCA1 or BRCA2 mutation?

In the 1990s, scientists discovered the genes BRCA1 and BRCA2 associated hereditary breast cancers4. If you have a rare pathogenic variant (aka mutation) in one of these genes, your chances of getting hereditary breast cancer within your lifetime can be over 70%5 The good news is that BRCA1,BRCA2 or other inherited breast cancer mutations are rare, with only about 1 in 400 people having them.6

MBS-funded BRCA testing is only available following specialist referral for women with a very high-risk of having a BRCA1 and BRCA2 gene variant based on family and clinical history.7 If you have a family history of breast or ovarian cancer, it’s a good idea to bring up hereditary breast and ovarian cancer (HBOC) testing with your doctor.

Can other genes (besides BRCA1 & BRCA2) increase my risk for breast cancer?

Yes. There are different levels of risk depending on “penetrance.” A high penetrance mutation in a gene like BRCA1 or BRCA2 increase your risk of developing breast cancer to a high level, like 70% lifetime risk.5 Mutations in other genes like CHEK2, are associated with more moderate penetrance, like a 25-30% lifetime risk, which still higher compared to an average women, but not as much as having a BRCA1 mutation8.

Finally, there are also low penetrance variants. These variants are more common. In fact, every woman has a few of them. Each variant carries a very small amount of breast cancer risk so they don’t have such a large effect on their own, but if you happen to have many of them, the risk adds up. We call this polygenic risk. Some women may have a lot of these small variants that can add to her risk of developing breast cancer, and some women may have very few of them—every woman has a different combination that can give us a hint at her risk of developing breast cancer.9

Your genetics can provide some insight into your risk, whether you are at risk of hereditary or sporadic breast cancer.

Is breast density important?

Yes, it is. Having very dense breast tissue on mammogram can double your risk of breast cancer.1 On top of that, having dense breasts also makes cancer more difficult to detect on a mammogram.10 

Breast density is usually measured at each mammogram, but it often isn’t reported back to the patient. If you’ve had a mammogram and don’t know your breast density, ask your doctor. Including your breast density in a risk assessment like geneType can make it easier to understand what your density means in combination with other important risk factors. If you haven’t had a mammogram yet you won’t know your breast density. You can still be assessed for risk with geneType for Breast Cancer even if you don’t know your breast density.

How can I better understand my personal breast cancer risk?

Clinical risk assessment models exist for women aged 35 years and older. GeneType for Breast Cancer is the best clinical product available to-date. It takes into account your polygenic risk, family history, age, body mass index (BMI), menopausal status and breast density to give you your personal risk of developing breast cancer.

Based on your risk level, you may be eligible for additional screening and risk reduction options. You are unique, your healthcare should be too.

Talk to your doctor about how a risk assessment like geneType for breast cancer could inform your personal breast health plan.

 

 

References

  1. Cancer Australia, 2018. Risk factors for breast cancer: A review of the evidence, Cancer Australia, Surry Hills, NSW.
  2. The Royal Australian College of General Practitioners. Guidelines for preventive activities in general practice. 9th edn, updated. East Melbourne, Vic: RACGP, 2018.
  3. Australian Institute of Health and Welfare 2019. Cancer in Australia 2019. Cancer series no.119. Cat. no. CAN 123. Canberra: AIHW.
  4. Petrucelli N, Daly MB, Pal T. BRCA1- and BRCA2-Associated Hereditary Breast and Ovarian Cancer. 1998 Sep 4 [updated 2022 Feb 3]. In: Adam MP, Ardinger HH, Pagon RA, Wallace SE, Bean LJH, Gripp KW, Mirzaa GM, Amemiya A, editors. GeneReviews® [Internet]. Seattle (WA): University of Washington, Seattle; 1993–2022.
  5. Kuchenbaecker KB, Hopper JL, Barnes DR, et al. Risks of Breast, Ovarian, and Contralateral Breast Cancer for BRCA1 and BRCA2 Mutation Carriers. JAMA. 2017;317(23):2402–241doi:10.1001/jama.2017.7112
  6. Maxwell KN et al. J Clin Oncol 2016;34:4183–5.
  7. Department of Health: MBS Online – Medicare Benefits Schedule, 2021. Category 6 – Pathology services. Item 73297.
  8. Tung, Nadine et al. “Counselling framework for moderate-penetrance cancer-susceptibility mutations.” Nature reviews. Clinical oncology vol. 13,9 (2016): 581-8. doi:10.1038/nrclinonc.2016.90
  9. Dite GS et al. Cancer Epidemiol Biomarkers Prev 2016;25:359–65. 
  10. Lee CI et al. Med Clin North Am 2017;101:725–41.
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