Published: 05 October 2023
NIHR has published its latest research Collection today - 'Why we need to understand breast cancer risk'.
This Collection highlights recent NIHR-funded research into breast cancer risk. It brings together a selection of studies that have investigated breast cancer risk and screening, including how:
- Risk-based approach could increase benefits of breast screening
- Healthy weight would prevent some breast cancers
- Family history increases some women’s risk but extra screening can help
A move towards more risk-based screening
Around 150 women every day are diagnosed with breast cancer in the UK.
The NHS Breast Screening Programme invites women aged 50-71 for breast screening every 3 years, with extra screening for those at high risk.
But the UK’s National Screening Committee is exploring the possibility of routine breast screening based on individual risk, rather than just age. This could increase the benefits and reduce the harms of screening.
This Collection draws together examples of research that could inform any move towards screening based on individual risk.
The evidence could also help health care professionals and women make informed decisions about their breast cancer risk. This could mean some cases are prevented or diagnosed earlier. The findings also provide reassurance that current screening helps prevent deaths from breast cancer.
Younger women might benefit from breast screening
It is well established that age is the main risk factor when it comes to getting breast cancer. 8 in 10 breast cancers are in women over 50.
Research in the Collection shows the NHS Breast Screening programme continues to prevent deaths from breast cancer. It also shows that benefits outweigh the risks of over-diagnosis (finding cancers that would never have caused the woman harm).
Yet, around 7,500 women in their 40s are diagnosed with breast cancer every year in the UK and there is a long-standing debate about the possible benefits and harms of screening younger women.
A long-term study featured in the Collection looked at the impact of annual breast screening for women in their 40s. The study involved more than 160,000 women and found women offered screening were 25% less likely to die of breast cancer in the first 10 years of the trial. For every 1,000 women screened, approximately one death was prevented. The risk of over-diagnosis was not higher among these younger women. This suggests that extending the screening programme to include women in their 40s may save lives and would not increase its harms.
This research could inform ongoing discussions about the possibility of routine breast screening being based on individual risk.
“The growing debate around risk-based screening reinforces the need for people to know more about breast cancer risk. The important NIHR-funded research highlighted in this Collection throws new light on risk factors, and how successful interventions to reduce risk are. We hope it will help women of all ages better understand issues of risk and screening, and aid healthcare professionals to support women to make informed decisions.” - Dr Jemma Kwint, NIHR Senior Research Fellow and author of the report
“The NHS breast screening programme is currently based on age with additional screening for women at very high risk. As more evidence emerges about the role played by other risk factors, there is increasing interest in whether tailoring screening according to each individual woman’s risk could increase the benefits and reduce the harms of screening.” - Rosalind Given-Wilson, Consultant Radiologist and member of UK National Screening Committee (UK NSC) and Chair of UK NSC Adult Reference Group
How can we help women at high risk?
Women have a higher risk of developing breast cancer if close relatives have had the disease. Long-term research from the Collection shows that some women with a family history of breast cancer are more likely to survive if they receive enhanced screening.
Those at high risk may be eligible to take a genetic test. But even so, answers are not clear-cut. For example, research also found that estimates of risk based on combinations of genes need to take ethnicity into account.
Those at the highest risk may be offered surgery to remove their breasts. Research showed this reduces the risk of cancer, but many women delay having the procedure. More support to make an informed choice could encourage some women to consider the option sooner.
This evidence could help health care professionals support women at high risk to reduce their chances of developing breast cancer.
“These issues are close to my heart. I was diagnosed with breast cancer aged only 45, 3 months after my mother died of it. I immediately had to have a unilateral mastectomy. Had I known at a younger age there were other steps I could take to reduce my risk, I would have taken them, including an elective bilateral mastectomy - Squirrel Kennedy, Public Contributor, Inverness
Myths and realities about breast cancer risk
The Collection also highlights a wide range of research about other factors that could affect risk.
For example, recent research, which included more than half a million women, suggests that women considering short-term hormone replacement therapy (HRT) for symptoms of the menopause can be reassured that HRT is linked to only a small increased risk of breast cancer.
Research also highlights that lifestyle factors are important. Factors such as alcohol consumption and weight impact a woman’s overall risk. A large study estimated the impact of being overweight or having diabetes on cancer risk. A high body mass index (BMI) was responsible for 7 in 100 breast cancers, and diabetes was responsible for 2 in 100 cases in women who had gone through the menopause. Maintaining a healthy weight could prevent some cases.
This evidence could inform the debate about individual risk-based screening. A better understanding of risk could also help people make informed decisions to reduce their chance of getting breast cancer.