NHS breast screening uses X-rays called mammograms to look for cancers that are too small to see or feel. This article explains who is invited and when, what happens at the appointment, what a call-back means and how the benefits and limits are described by the NHS and Cancer Research UK.
Who is invited, and how often?
According to the NHS, breast screening is offered to women aged 50 up to their 71st birthday. The first invitation arrives automatically between the ages of 50 and 53, and further invitations follow every three years until the 71st birthday. Invitations depend on being registered with a GP surgery, so keeping those details up to date matters.
A simple worked example shows what that pattern means. Someone invited at 50 and attending every time would be offered screening at 50, 53, 56, 59, 62, 65 and 68: seven appointments. The next would fall at 71, which is not offered automatically. This is illustrative arithmetic; the real first invitation may come at any point between 50 and 53, so the dates shift accordingly.
Anyone who has not been invited by 53 and believes they should have been can contact their local breast screening service, the NHS says.
What about women over 71, and trans and non-binary people?
Women aged 71 or over are not invited automatically, but the NHS says they can still be screened every three years by calling their local breast screening service to ask for an appointment. Cancer Research UK adds that overdiagnosis, discussed below, becomes more likely with age, which is part of why the programme stops sending routine invitations.
For trans and non-binary people, the NHS explains that invitations follow the sex a person is registered as at their GP surgery:
| Situation | What the NHS says |
|---|---|
| Registered female | Automatically invited |
| Registered male | Not invited automatically; contact the GP surgery or local service to ask for an appointment |
| Assigned male at birth, on feminising hormones for more than two years | Can have screening; ask the GP or local service |
| Assigned female at birth, has had top surgery | Mammograms are unlikely to be possible; speak to a GP about any chest changes |
Is screening the same as checking for symptoms?
No. Screening is for people who have no symptoms. Both the NHS and Cancer Research UK are clear that anyone who notices a change in their breasts should see a GP promptly rather than waiting for the next invitation, and that a normal screening result does not remove the need to stay alert between appointments.
The NHS advises checking your breasts between mammograms and seeing a GP about any changes, even if your last screening was normal. A more detailed look at how the NHS handles symptoms is beyond what a screening programme covers, and a GP or pharmacist is the right first contact.
What happens at the appointment?
The NHS says the whole appointment should take no longer than 30 minutes, with the mammograms themselves taking only a few minutes. The sequence is straightforward:
- A female mammographer checks your details and asks about any past breast problems.
- You undress above the waist in private.
- The mammographer positions each breast on the machine, which involves touching it, and holds it between two plastic plates for a few seconds while you keep still.
- You have four X-rays in total, two of each breast, and then get dressed in private.
On the practical side, the NHS suggests wearing a top that is easy to take off rather than a dress or jumpsuit, removing necklaces and nipple piercings, and removing any binder before the appointment. It also advises not using deodorant, antiperspirant or talcum powder that day, because these can affect the images.
The NHS says screening is often uncomfortable and can be painful for some people, though any discomfort should pass quickly. You can ask the mammographer to stop at any time, and it helps to mention if you have difficulty standing or walking or have found screening uncomfortable before.
How and when do results arrive?
The NHS says results usually come by letter within two weeks of the appointment, and your GP receives them too. Sometimes another mammogram is needed first, which can delay the letter. If the wait is longer, you can call the breast screening service for an update; a longer wait does not mean something is wrong.
Most people have no sign of cancer. If more tests are needed, the NHS says you will be given an appointment, and the letter explains how to contact a breast care nurse.
What does being called back actually mean?
A call-back is not a diagnosis. According to the GOV.UK guide to NHS breast screening, for every 100 people who have breast screening, 4 will need further tests, and of those 4, 1 will be diagnosed with breast cancer. Cancer Research UK gives the same figure for call-backs, around 4 in 100, and notes that many of those women do not have cancer.
Further tests, as the NHS describes them, may include:
- a breast examination
- more mammograms
- ultrasound scans
- a biopsy, in which a small sample is taken with a needle
Scaling the published figures up gives a feel for the numbers. Out of 1,000 women screened, 4 in 100 is 40 women asked back for more tests; if 1 in 4 of those is diagnosed, that is 10 women. Cancer Research UK separately says screening finds cancer in around 9 out of every 1,000 women screened, which is in the same range. These are illustrative calculations from rounded published figures, not a forecast for any individual.
The NHS adds that finding cancer early may make it easier to treat and less likely that a breast will need to be removed.
What are the benefits, and what are the limits?
Cancer Research UK says screen-detected cancers are generally early-stage and usually easier to treat. It estimates that breast screening reduces breast cancer deaths by about 1,300 a year in the UK, and reports that nearly 19,300 breast cancers were diagnosed through screening in England between 2024 and 2025.
The same page sets out the downsides honestly:
- Overdiagnosis. A 2012 review estimated that around 4,000 women in the UK are overdiagnosed each year, meaning a cancer is found and treated that would never have caused harm. The GOV.UK guide likewise warns that screening may find a cancer that would never have caused harm.
- False results. Both false positives, which lead to unnecessary worry and tests, and false negatives occur. The GOV.UK guide says very rarely a cancer may be missed.
- Radiation. The GOV.UK guide says the X-ray dose very slightly increases the chance of getting cancer over a lifetime. Cancer Research UK says this applies to mammograms every three years for 20 years.
- Younger women. Cancer Research UK says the evidence shows harms outweigh benefits for women under 50, and that denser breast tissue, mainly in younger women, makes mammograms harder to read.
Because these trade-offs exist, the NHS frames screening as a personal choice, and the GOV.UK guide is titled to help women decide.
Is screening different if family history raises the risk?
Yes. Routine screening is designed for women at average risk. Cancer Research UK says women with a moderate or high family history should start yearly mammograms in their forties, and that yearly MRI scans are recommended from age 20 for a TP53 gene change and from age 30 for BRCA1 or BRCA2 changes. Anyone worried about family history should talk to a GP, who can advise on referral rather than waiting for the routine invitation.
Making screening easier to attend
Practical obstacles are common: finding the time, anxiety about discomfort or concerns about the exam itself. Employers have a part to play, and the principles in flexible working requests show how time for health appointments can be raised. Midlife is also when many women are juggling work and health changes, as covered in menopause at work. Breast screening sits alongside other NHS programmes, such as cervical screening and home test kits, each with its own ages and intervals.
A three-yearly choice worth understanding
The programme is simple in outline: from 50 to the 71st birthday, a letter every three years, a short appointment and a result within about two weeks. What the figures show is a test that finds many cancers early, calls back a small minority for further checks and carries real but limited downsides. Knowing those numbers in advance makes the letter easier to open, and any new breast change is always a reason to contact a GP straight away.
This article is general information, not medical advice. For questions about your own screening, symptoms or family history, speak to your GP, practice nurse or pharmacist.
Sources: NHS (Who breast screening is for); NHS (What happens at your breast screening appointment); NHS (Your results); GOV.UK (NHS breast screening: helping you decide); Cancer Research UK (Breast screening)
