Actress Olivia Munn recently shared on social media that she had undergone a double mastectomy after being diagnosed with . In , Munn explained how she had been diagnosed with the fast-growing cancer.
Author
Justin Stebbing
Professor of Biomedical Sciences, Anglia Ruskin University
The actress had initially undergone genetic testing in an effort to be proactive about her health. Munn tested negative for mutations of the BRCA gene, which is associated with a . Still, Munn’s doctor decided to calculate her “Breast Cancer Risk Assessment Score” by looking at other factors known to increase risk of the disease.
The test revealed Munn had a 37% risk of developing breast cancer in her lifetime. Munn subsequently decided to undergo further testing, which revealed she had cancer. Many people reading this story may be wondering whether they should also have a breast cancer risk assessment done – and what this would entail.
In general, a breast cancer risk assessment involves evaluating various factors that can contribute to a person’s likelihood of developing breast cancer. Some factors that would be taken into consideration include:
1. Age
Age is a major risk factor for breast cancer. The older you are, the more likely you are to .
About 80% of breast cancer cases occur in woman over 50, who have been through the menopause. This is one reason why all women aged 50-71 should be every three years.
2. Family history
Having a mother, sister or daughter (referred to as a “first-degree relative”) diagnosed with breast cancer approximately . This risk is even higher the more close relatives you know who have had breast cancer, or if a relative developed breast cancer under the age of 50.
While family history of breast cancer on your mother’s side is associated with greater risk, history of breast cancer on the father’s side shouldn’t be either.
3. Genetic mutations
Mutations in genes such as are associated with a higher risk of breast cancer and ovarian cancer, with these cancers occurring at younger ages.
About at some point in their lives and most of these cases do not have predisposing mutations, . By contrast, most women who inherit a harmful BRCA1 or BRCA2 gene variant by 70-80 years of age if they aren’t followed up and treated properly, for example with bilateral (meaning both sides) mastectomies.
But these may not be the only genetic mutations which increase breast cancer risk. In Munn’s case, although she didn’t have a BRCA mutation, she may have had other genes which we’re now understanding have a role – such as the or the .
Importantly, genetic tests are now much quicker and easier to access than they used to be – and on the NHS.
4. Medical history
Previous breast biopsies and benign breast conditions (such as fibroadenomas or pre-cancerous lesions in the breast tissue) would all be taken into account as they can be associated with an increase breast cancer risk.
A doctor would also look at a person’s hormonal and reproductive health, looking specifically at when they had their , when they had their and if they were .
Research explored the mechanisms by which delaying a first pregnancy to the late-30s increases the . We discovered that changes that occur in the breast’s tissues during pregnancy can ultimately trigger more mutations to occur in the breast’s tissue over time.
5. Breast density
Having very dense breasts is a risk factor for breast cancer and is associated with a .
A person is considered to have if they have high amounts of glandular tissue and connective tissue and low amounts of fatty breast tissue. can only be seen on mammograms.
6. Lifestyle
Factors such as whether a person , what their , how they are, if they’re and if they take , may all linked with greater risk of breast cancer. Your doctor will take all of these into account when assessing your risk.
is a particularly important factor, as excess alcohol use is associated with greater risk. Even moderate alcohol consumption can .
7. Radiation exposure
Having previously for lymphoma, especially during childhood and adolescence, may increase the risk of breast cancer – though this is rare.
It’s important to note that this is only referring to radiation treatment. Routine X-rays should not increase your breast cancer risk.
Caveats and limitations
This isn’t an exhaustive list and other factors can be important. For example, are up to 20% more likely to develop postmenopausal breast cancer than older, non-diabetic women – but this may be related to obesity.
Calculating breast cancer risk typically involves integrating these factors into risk assessment models – sometimes called risk calculators. These models use statistical algorithms to estimate a person’s likelihood of developing breast cancer over a period of time by giving the average risk of breast cancer for a group of women with similar risk factors.
For example, say it gives a woman a five-year risk of 1%. This means the tool estimates 1% of women who have similar risk factors will develop breast cancer over the next five years. However, it can’t predict which of these women will get breast cancer.
While these risk assessment tools can provide valuable information, they are not perfect predictors. Personalised medical advice should always be sought from healthcare professionals, and you should have more than one discussion before undergoing any preventative treatment.
Justin Stebbing does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.
