What do we know about Breast Cancer Risk?
Breast cancer is the most common cancer in the UK and thus is a concern for many women. Around 150 women a day develop breast cancer, and approximately 1 in 8 women will develop it in their lifetime. Thankfully, breast cancer survival has improved significantly over the last few decades and most women recover because of the availability of screening, early diagnosis, and improved treatments.
Causes of Breast Cancer
The causes of breast cancer aren’t fully understood, but research is increasing our knowledge about the risk factors (https://www.nhs.uk/conditions/breast-cancer/causes/. Age and biological sex have the greatest impact, and the risk is highest in women over the age of 50.
Further risk factors include a previous history of breast cancer, family history, gene mutations such as BRCA1 and BRCA2, younger age at first period, older age at menopause, and ethnicity.
Lifestyle factors, such as lack of exercise, smoking, alcohol, and being overweight over the age of 50, are also associated with an increased risk, and in fact, 1 in 4 breast cancers are thought to be preventable through lifestyle choices, such as maintaining a healthy weight, being physically active and avoiding alcohol.
Although breast cancer is commonest in women over the age of 50, around 7,600 women in their 40s are diagnosed with breast cancer every year in the UK. However, the NHS Breast Screening Programme, which uses special X-rays called mammograms to examine the breasts, only starts from age 50.
There’s been a lot of debate about whether screening should start earlier than 50, because although earlier screening might reduce deaths from breast cancer, it’s possible that it might also cause harm as a result of overdiagnosis of cancers that would not have caused harm, leading to unnecessary distress, and treatment with drugs, surgery and/or radiotherapy that provide no benefit.
Research has been done to understand the impact of offering yearly mammography to women in their 40s, and a study found that screening these younger women prevented breast cancer deaths in the first ten years but not afterwards. It did not increase over-diagnosis compared to the current programme, suggesting that women in their 40s might benefit from annual screening.
So why is screening not offered to younger women?
In women aged 50 – 69 years in the NHS Screening Programme, 9 breast cancer deaths are prevented for every 1,000 women who attend screening. In the study in younger women described above, one death was prevented for every 1000 women screened, but also women screened were 25% less likely to die of breast cancer in the first 10 years of the trial had a similar reduction in risk of death beyond 10 years as in women who were screened over age 50, and no increased risk of death from other causes.
The main reason for not offering routine screening to younger women is cost. Where budgets are limited, as in the NHS, other screening programmes also compete for the same budget. Therefore, screening programmes must be cost-effective (good value for money), and this needs to be explored for younger women.
So, what happens next?
Studies are looking at more advanced ways to screen and to improve attendance for screening which might mean that more breast cancer deaths could be prevented in women in their 40s.
Risk-based screening, based on specific risk factors for breast cancer rather than age, is currently being considered. This is based on the fact that a family history of certain types of breast cancer or inheriting breast cancer-associated genes significantly increases a person’s risk.
However, before risk-based screening can be routinely implemented, it’s important to understand whether this is cost-effective, its impact on the healthcare system and whether it contributes to health inequalities; for example, some risk calculators developed in European populations, may overestimate the risk of breast cancer in Black, Asian and Jewish women. Among other harms, this may result in unnecessary anxiety or treatment and cause women to distrust the health service and disengage from care.
Risk factors for breast cancer
Family History and Genetic Risks
Women have a higher risk of developing breast cancer if they have close relatives who’ve had it. Women with a family history of breast cancer can be divided into 3 groups: those with a similar risk of developing breast cancer to the general population (less than 17%), those with moderate risk (17-29%), or those at high risk (30% or more).
Individuals at high risk may wish to take a genetic test as studies show that for women with the BRCA1 or BRCA2 genes, risk-reducing surgery to remove their breasts significantly reduces their risk of breast cancer.
Lifestyle
A healthy lifestyle that pays attention diet, exercise, stopping smoking, maintaining a healthy weight and reducing alcohol intake, has also been shown to reduce the risk of breast cancer.
In the UK, almost 2 in 3 adults are living with obesity or overweight. This increases the risk of many different types of cancer, as well as type 2 diabetes. A large study showed that being overweight or having diabetes, either individually or together increased the risk of breast cancer.
Breast cancer and HRT
Because breast cancer screening begins in the 50s, this coincides with the onset of menopause for most women, and many women choose to take hormone replacement therapy (HRT) to relieve their menopause symptoms, which may be extremely unpleasant for many and debilitating for others.
Over the years, HRT has attracted a lot of negative media attention, because of past research that suggested that it might be harmful. Some of these studies suggested that HRT might be associated with an increased risk of breast cancer.
However, more recent research shows that HRT is safe for the majority of women under age 60 and has many benefits which may not be mentioned in discussions about possible risks, including control of symptoms, a reduced risk of cardiovascular disease, osteoporosis and possibly dementia in some women.
Recent research shows that HRT is generally linked to only a small increased risk of breast cancer. For example, using HRT for less than 5 years would be linked to 9 extra cases of breast cancer in a group of 10,000 women in their 50s; that is less than 1 in 1000 women.
The risk increased if HRT was taken for more than 5 years but fell when HRT was stopped. The risk of breast cancer with HRT is also linked to whether a progestogen (synthetic form of progesterone) is taken with estrogen (combined HRT) – estrogen-only HRT is not associated with an increased risk of breast cancer, and there is some evidence that natural progesterone and newer progestogens may not carry the same risk. What’s also important to know is that women who develop breast cancer on HRT don’t die of it. This may be because cancers in these women are diagnosed and treated earlier.
It’s really important to look at the breast cancer risk with HRT in the context of the risk associated with other conditions. For example, the risk of breast cancer associated with being overweight over the age of 50 is greater than that with combined HRT. Approximately 2% of breast cancer cases in the UK are thought to be related to the use of HRT, compared to about 8% of cases related to alcohol use, and being overweight is also associated with a greater risk.
Why New Woman Health?
At NewWoman Health we have a commitment to educating, advising, treating, and supporting women approaching, during, and following menopause. Our wide range of medical and lifestyle interventions helps women to manage or minimise their menopause symptoms and improve their quality (and potential longevity) of life in an aspirational and uplifting way.
If you’re concerned about your menopause transition and/ or other menopause-related problems, including treatment options, we can support you with our personalised medical consultations with menopause specialists. Take the next step in ensuring your long-term health and quality of life by booking a consultation with us today.
