Space 01 · Understand

Risk factors

Chapter 03 of 15 · 8 cards · about 5 min

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Chapter 03 · Risk factors
THE QUESTION

Why do some people get breast cancer and others don't?

The answer in a few cards.

1 / 8

What is a risk factor?

Something that increases the chance of getting the disease. It is not a certain cause: you can have risk factors and never become ill.

Source: ACS, 2026

2 / 8

Half of women have no particular factor

About half of breast cancers affect women with no risk factor other than being a woman and being over 40.

Source: WHO, 2024

3 / 8

Being a woman and getting older

Being a woman is the main risk factor. The risk also rises with age.

Source: ACS, 2026

4 / 8

Family and genes

Having a mother, sister or daughter with breast cancer increases the risk. About 5 to 10% of breast cancers are inherited.

Source: ACS, 2026

5 / 8

A lifetime of hormones

Periods that start early, a late menopause, a late first pregnancy or no pregnancy slightly increase the risk.

Source: ACS, 2026 · American Cancer Society (ACS), 2026

6 / 8

Alcohol and tobacco

Drinking alcohol increases the risk, and the more you drink, the higher it gets. Tobacco is also a risk factor.

Source: American Cancer Society (ACS), 2026 · WHO, 2024

7 / 8

Weight and movement

Being overweight after menopause and a lack of physical activity increase the risk.

Source: American Cancer Society (ACS), 2026

8 / 8

Some hormone treatments

Some menopausal hormone treatments increase the risk. Talk to your doctor about it.

Source: American Cancer Society (ACS), 2026

DID YOU KNOW?

A large analysis of 47 studies showed that the risk drops by about 4.3% for each year of breastfeeding.

Source: The Lancet, 2002;360:187-195, 2002

TRUE OR FALSE?

“With no cases in my family, I'm not at risk.”

TRUE OR FALSE?

“Alcohol increases the risk of breast cancer.”

KEY POINTS
  • Age, family, hormones, alcohol, weight and inactivity all play a part.
  • Having a risk factor does not mean being ill.
  • All women should stay alert.
SOURCES FOR THIS CHAPTER

Information based on publications by the WHO, the International Agency for Research on Cancer (IARC), the French National Cancer Institute, the American Cancer Society, the National Cancer Institute, Cancer Research UK and published scientific studies. The information on ROSE does not replace the advice of a health professional.

Chapter complete!

You now know more than many people. Pass it on.

Next chapter: Screening, by country and age →
Sources: American Cancer Society (ACS), 2026 · ACS, 2026 · The Lancet, 2002;360:187-195, 2002…

15 stories to understand it all

Pick a question and let the cards guide you.

01To readWhat is breast cancer?Is a lump in the breast always cancer?5 min read02To readThe signsWould you recognise breast cancer?5 min read03In progressRisk factorsWhy do some people get breast cancer and others don't?5 min read04To readScreening, by country and ageShould you wait for a sign before getting a test?5 min read05To readDiagnosis and testsThey found a lump: what happens next?5 min read06To readTypes: hormone-sensitive, HER2, triple-negativeAre all breast cancers the same?5 min read07To readStagesWhat does “stage 2” mean?5 min read08To readTreatmentsHow is breast cancer treated?5 min read09To readLiving with treatment side effectsFatigue, hair, morale: how to get through treatment?5 min read10To readLife afterAnd when treatment is over?5 min read11To readGenetics and BRCAIs breast cancer passed down in families?5 min read12To readBreast cancer in menCan a man get breast cancer?5 min read13To readYoung womenI'm under 40: can it happen to me?5 min read14To readSupporting a loved oneHow can you help someone with breast cancer?5 min read15To readPreventionCan you reduce your risk of breast cancer?5 min read

Information based on publications by the WHO, the International Agency for Research on Cancer (IARC), the French National Cancer Institute, the American Cancer Society, the National Cancer Institute, Cancer Research UK and published scientific studies. The information on ROSE does not replace the advice of a health professional.