Can a Mammogram Cause Cancer? Radiation, Pain and Squeezing

Quick facts

Radiation risk: A mammogram every 3 years for 20 years gives a very slightly higher lifetime chance of cancer; Source: NHS: Why breast screening is done
Dose: About the same as flying from London to Australia and back, says one NHS trust; Source: Newcastle upon Tyne Hospitals NHS Foundation Trust: Breast screening FAQs
The squeeze: Lasts a few seconds and does not cause any harm to the breasts; Source: Newcastle upon Tyne Hospitals NHS Foundation Trust: Breast screening FAQs
Main risk of screening: Finding a cancer that would never have caused harm; Source: NHS England (GOV.UK): NHS breast screening – helping you decide

Key takeaways

Mammograms use a small amount of radiation that very slightly increases your lifetime chance of cancer. (NHS England (GOV.UK): NHS breast screening – helping you decide)
The NHS says the main risk of breast screening is treating cancers that would not have been life-threatening. (NHS: Why breast screening is done)
Squeezing the breast during a mammogram does not cause or spread breast cancer, says The Royal Marsden NHS Foundation Trust. (The Royal Marsden NHS Foundation Trust: Busting breast cancer myths)
Breast screening is often uncomfortable and sometimes painful, but any discomfort should not last long, and you can ask to stop at any time. (NHS: What happens at your breast screening appointment)
Mammograms do not find every cancer, so keep checking your breasts and contact a GP about any change. (NHS England (GOV.UK): NHS breast screening – helping you decide)

How much radiation does a mammogram use?

A mammogram is an X-ray of the breast, so it exposes you to a small amount of radiation. The NHS says having a mammogram every 3 years for 20 years gives you a very slightly higher chance of getting cancer over your lifetime.

NHS England’s screening leaflet says NHS machines use low radiation doses to minimise any risk, and that research shows the overall benefits of breast screening outweigh the risks of radiation exposure.

Newcastle upon Tyne Hospitals NHS Foundation Trust puts the dose at about the same as a person receives flying from London to Australia and back. NHS inform adds that everyone is exposed to background radiation in daily life.

Sources: NHS: Why breast screening is done; NHS England (GOV.UK): NHS breast screening – helping you decide; Newcastle upon Tyne Hospitals NHS Foundation Trust: Breast screening FAQs; NHS inform (Scotland): Breast screening

Can squeezing the breast spread cancer?

No. The Royal Marsden NHS Foundation Trust says the compression of the breast during a mammogram does not cause or spread breast cancer.

The squeeze holds the breast still. North Tees and Hartlepool NHS Foundation Trust explains that it lasts only a few seconds, does not cause any harm, and is needed to get the clearest picture with the lowest amount of radiation possible.

Sources: The Royal Marsden NHS Foundation Trust: Busting breast cancer myths; North Tees and Hartlepool NHS Foundation Trust: Breast screening FAQs

Does a mammogram hurt?

It can. The NHS says breast screening is often uncomfortable and sometimes painful for some people, but any discomfort should not last long. The mammographer is trained to help you feel more comfortable, and you can ask to stop at any time. It may help to tell staff if you have found screening uncomfortable before.

Each breast is squeezed between 2 pieces of plastic for a few seconds. Newcastle Hospitals says any pain usually disappears shortly afterwards, though a small number of women have pain for longer.

Sources: NHS: What happens at your breast screening appointment; Newcastle upon Tyne Hospitals NHS Foundation Trust: Breast screening FAQs

What are the real downsides of breast screening?

The NHS says the main risk is finding a cancer that would never have caused harm. Doctors cannot always tell whether a cancer will become life-threatening, so treatment is always offered. This means some people are treated for cancers that would not have been life-threatening.

No screening test is 100% reliable. Very rarely a cancer may be missed, and breast cancer can also develop between screening appointments.

The NHS says most people feel the benefits of breast screening outweigh the possible risks, and that it is your choice whether to have it.

Sources: NHS: Why breast screening is done; NHS England (GOV.UK): NHS breast screening – helping you decide

Which breast changes should you get checked?

Because screening can miss cancers, know what is normal for you and see a GP or doctor about any change, even if you have recently had a mammogram. The NHS lists:

a lump or swelling in your breast, chest or armpit
a change in the skin of your breast, such as dimpling (it may look like orange peel)
a change in skin colour – on white skin it may look red, on black or brown skin it may look darker than usual
a change in the size or shape of one or both breasts
nipple discharge (if you are not pregnant or breastfeeding), which may have blood in it
a change in the shape or look of your nipple, such as it turning inwards or a rash on it

In the UK, do not wait for your next screening appointment.

Sources: NHS: Symptoms of breast cancer in women; NHS: Who breast screening is for

Frequently asked questions

How does mammogram radiation compare with everyday life?

NHS inform says each mammogram gives a very small amount of radiation, so the risk is very low. Everyone is exposed to background radiation in daily life, and the exact amount depends on where you live, how many flights you have taken and even what you have eaten.

Source: NHS inform (Scotland): Breast screening

Does squeezing during a mammogram cause cancer?

No. The Royal Marsden NHS Foundation Trust says compression of the breast during a mammogram does not cause or spread breast cancer. The breast is pressed flat to get higher-quality X-ray images of the tissue.

Source: The Royal Marsden NHS Foundation Trust: Busting breast cancer myths

How long does mammogram discomfort last?

The NHS says breast screening is often uncomfortable and sometimes painful for some people, but any discomfort should not last long. You can talk to the mammographer, who is trained to help you feel more comfortable, and ask to stop at any time.

Source: NHS: What happens at your breast screening appointment

Can I wear deodorant to a mammogram?

NHS England asks you not to use deodorant, antiperspirant or talcum powder on the day of breast screening, as this may affect the mammogram. It also suggests wearing a top that is easy to remove and taking off necklaces and nipple piercings.

Source: NHS: What happens at your breast screening appointment

What is overdiagnosis in breast screening?

It means finding a cancer that would never have caused harm. NHS England’s leaflet calls this the main risk of breast screening, because doctors cannot always predict which cancers will become life-threatening, so treatment is offered whenever breast cancer is found.

Source: NHS England (GOV.UK): NHS breast screening – helping you decide

Do mammograms find every cancer?

No. NHS England’s leaflet says no screening test is 100% reliable. Very rarely a cancer may be missed, and breast cancer can develop between screening appointments, so keep looking at and feeling your breasts and contact a GP about any unusual changes.

Source: NHS England (GOV.UK): NHS breast screening – helping you decide

Sources and references

This page is general information, not medical advice. A GP or doctor can advise on your own situation. Source links do not imply endorsement by the NHS or another organisation. See our editorial policy.