Breast cancer
Signs, screening and myths
What breast cancer is, the warning signs to look out for and how to detect it early.
Learn
Breast cancer risk factors
Some factors increase the likelihood of developing breast cancer. Some cannot be changed; others can be acted upon in everyday life.
A risk factor is not destiny
Having one or more risk factors does not mean you will get cancer. And having none does not fully protect you: about half of all breast cancers occur in women with no risk factor other than sex and age. Early detection therefore concerns every woman.
Factors you cannot change
Knowing them helps you stay alert and talk about them with your health professional.
Being a woman
This is the main risk factor: the vast majority of breast cancers affect women.
Age
The risk increases with age, especially after 50, even though younger women can be affected.
Family history
The risk is higher if a mother, sister or daughter has had breast cancer, especially before 50, or if several relatives on the same side of the family have been affected.
Certain inherited genetic mutations
Mutations in genes such as BRCA1, BRCA2 or PALB2 greatly increase the risk of breast (and ovarian) cancer. They remain rare.
A personal history
Having already had breast cancer, or certain so-called “atypical” benign lesions, increases the risk of developing another.
Chest radiotherapy in childhood or youth
For example to treat lymphoma. Special monitoring is then offered.
Dense breasts
Dense breast tissue, visible on a mammogram, is associated with a slightly higher risk and makes images harder to read.
Factors linked to hormonal and reproductive history
They reflect a longer or shorter exposure to female hormones over a lifetime.
Early periods or late menopause
First periods before age 12 or menopause after 55 lengthen exposure to hormones.
A late first pregnancy or no pregnancy
A first full-term pregnancy after 30, or never having been pregnant, is associated with a slightly higher risk.
Menopausal hormone therapy
Combined treatments (oestrogen and progestogen) increase the risk, especially when taken for several years. The risk falls after stopping.
Hormonal contraception
It is associated with a slight increase in risk while it is being used, which fades gradually after stopping. Its benefits remain significant: talk to your health professional, and do not stop contraception without advice.
Lifestyle factors
These are the ones every woman can act on, and they are good for your health in general.
Alcohol
The risk increases with the amount consumed, even with small regular amounts. There is no risk-free level.
Overweight and obesity
After menopause, excess weight increases the risk of breast cancer.
Lack of physical activity
A sedentary lifestyle is associated with a higher risk. Moving regularly is protective.
Tobacco
Smoking is associated with an increased risk of breast cancer, on top of its many other harms.
Habits that protect
According to the WHO, these habits help reduce the risk of breast cancer:
Breastfeed
Breastfeeding, especially for longer periods, reduces the mother’s risk of breast cancer.
Move every day
Brisk walking, dancing, active work: aim for at least 150 minutes of moderate activity a week.
Keep a healthy weight
A diet rich in vegetables, fruit, pulses and whole grains helps.
Limit alcohol
The less you drink, the better. Not drinking at all is the safest choice.
Avoid tobacco
Not smoking and avoiding other people’s smoke protects against many cancers.
Get regular check-ups
Have your breasts examined regularly and tell your health professional about your family history.
Family history: when should you mention it?
Talk to a doctor, who can offer appropriate follow-up or a genetic consultation where available, if in your family:
- several women on the same side of the family have had breast or ovarian cancer;
- a relative had breast cancer before the age of 40 or 50;
- a relative had cancer in both breasts;
- a man in the family has had breast cancer;
- a BRCA1, BRCA2 or PALB2 mutation has already been found in a family member.
Gather what you know (who, which cancer, at what age) before your appointment: this information helps the doctor assess your situation.
Take action now
Learn how to examine your breasts and get checked regularly.
Learn more
Practical guide
Breast self-exam, step by step
An illustrated six-step guide, a printable checklist and a monthly reminder for your phone.
Cervical cancer
HPV, vaccination and screening
A cancer that can almost always be prevented through vaccination and screening.
Sources
The information on this page is based on publications by the World Health Organization (WHO) and the International Agency for Research on Cancer (IARC).
For information only
This information does not replace a medical consultation. It cannot be used to make a diagnosis or to choose a treatment. For any question about your health, or if you notice a change, see a doctor, a midwife or a health centre.
Content reviewed on 3 October 2026