What is breast screening?

Breast cancer is the most common cancer in women in the UK. But it can usually be treated and cured if it’s found early. Breast screening is a way of finding a breast cancer when it is too small to see or feel. It involves having a mammogram, which is a type of x-ray.

All women registered with a GP aged 50–70 (or 47-73 in England) will be invited to be screened every three years. It’s rare for women under 50 to develop breast cancer so they aren’t automatically screened.

Breast screening cannot prevent cancers. It can only find cancers that are already there. Research estimates that breast screening can reduce deaths by up to 20%. If a cancer is found, it is often very small and hasn’t spread. This means it is usually easier to treat.

However, there are some disadvantages of breast screening. There is a chance of being diagnosed and treated for a breast cancer that would not have caused any problems. It can also be uncomfortable and cause worry for lots of women.

How common is breast cancer?

Breast cancer is the most common cancer in women. Nearly 50,000 women in the UK are diagnosed with breast cancer each year.

One in eight women in the UK will develop breast cancer at some time in their life. However, it can usually be cured if it's found early.

Breast cancer almost never occurs in women in their teens or early twenties and it is rare in women under 35. As women get older, their risk of developing breast cancer increases. Eight out of ten breast cancers (80%) occur in women aged 50 or over.

Breast screening

Breast screening  is a way of finding breast cancers early, when they are too small for you or your doctor to see or feel. The first stage of breast screening is a mammogram. A mammogram is an x-ray of each breast.

Under the present Department of Health guidelines, all women registered with a GP and aged 50–70 are offered a mammogram every three years. If you’re older than this you won’t be automatically invited for breast screening, but you can still have mammograms by making your own appointment every three years. It’s important to do this, as the risk of developing breast cancer increases as women get older.

In England, the age range is gradually being extended to include women aged 47–73 by 2016. Scotland, Wales and Northern Ireland will continue to screen women aged 50–70.

If you’re under 50

Women younger than the screening age aren’t routinely offered breast screening because large research trials have shown that regular screening of this group doesn’t help to save lives. Breast cancer is uncommon in women under 50, and mammograms are less effective at detecting breast cancer in women who haven’t had their menopause. The menopause happens, on average, around the age of 50. After the menopause the breast tissue is less dense, which makes mammograms easier to read and the results more reliable.

Women under the screening programme age who have an increased risk of breast cancer because of a family history should be offered regular screening. This may involve a different type of screening test called magnetic resonance imaging (MRI).

We have more information about breast screening in women under 50 with a family history of breast cancer.

Although mammography can be less reliable in women under 50, new mammography techniques using digital images are being introduced that are more useful at detecting breast cancers in younger women.

We have more information about how you get a breast screening appointment and what happens at the appointment.

If you’re over 70

If you’re over 70, you can still have screening because you are still at risk of breast cancer. You won’t receive an invitation letter but you can contact your local screening clinic every three years to arrange a mammogram.

What happens during breast screening?

In this video, made by healthtalk.org, people affected by cancer share their experiences. They may not be the same as yours, or reflect your situation. Talk to your healthcare team if you have any questions. © University of Oxford

About healthtalk.org videos

What happens during breast screening?

In this video, made by healthtalk.org, people affected by cancer share their experiences. They may not be the same as yours, or reflect your situation. Talk to your healthcare team if you have any questions. © University of Oxford

About healthtalk.org videos

Benefits of breast screening

Regular breast screening using mammography is the best way to detect early breast cancers as they are often more successfully treated. Large research trials estimate that breast screening can help reduce the risk of dying from breast cancer by 20%. However, as well as helping to save lives there are some potential disadvantages to breast screening. To help you decide whether to go for screening, the main benefits and disadvantages are described here.

Breast screening finds cancers early

In women who have breast screening, most cancers are found at an early stage when there is a good chance that treatment will be successful. In the UK more than half of the breast cancers found through screening are discovered very early – when they are very small and haven’t spread to the lymph nodes close to the breast.

Breast screening saves lives

Nearly three million women are invited for breast screening in the UK every year. Almost three quarters of those invited attend for screening. Out of these around 17,000 breast cancers are found. Research shows that screening programmes probably prevent about 1300 women dying from breast cancer every year.

Different treatments are possible

If breast cancer is found early, it is likely to be small. This means that breast conserving treatment may be possible. This is when a surgeon can usually remove the cancer and some surrounding tissue, followed by radiotherapy. Breast conserving treatment can be done instead of removing the whole breast in a mastectomy. Around 70% of women (7 out of 10) diagnosed through screening have breast conserving treatment. This is compared with 55% of women diagnosed without having screening.

Disadvantages of breast screening

Breast screening can’t prevent cancer

It only helps to find a breast cancer if it’s already there.

Having a mammogram is uncomfortable

Many women find having a mammogram uncomfortable or even painful, but this is normally just for a short time. Some women may feel tender in the area for a few days afterwards. Painkillers can help with this.

Having a mammogram involves x-rays

All x-rays, including mammograms, involve a small amount of radiation. The amount of radiation given during a screening appointment is very small and unlikely to cause any harm.

The radiation dose given by breast screening x-rays is continually monitored to make sure that it is as low as possible while still giving a good-quality image. X-ray machines are also carefully checked to make sure that they don’t accidentally expose people to too much radiation.

If you’re concerned about the risk of having a mammogram, talk to the staff at the screening unit.

Results may cause unnecessary worry

Mammograms can sometimes show an abnormal area in the breast, which further tests show isn’t a cancer. This is called a false-positive result. About 4% of women (4 in every 100) who have breast screening will have an abnormal result and be asked to go for further tests. These tests may include more mammograms, ultrasounds or removing a small piece of breast tissue (biopsy). 75% of the women (3 out of 4) asked back for further tests won’t have breast cancer.

Waiting to get the results of these further tests can be very worrying. Some women may still feel anxious even after the doctor or nurse has told them they don’t have breast cancer.

Mammograms sometimes need to be repeated

1–2% of mammograms (1–2 in every 100) have to be taken again. This is because:

  • the mammogram has missed part of the breast tissue
  • the x-ray picture is blurred
  • there’s a problem with the equipment, but this is rare.

Breast screening occasionally misses a cancer

Although mammography is the most effective and reliable way of detecting breast cancer early, it isn’t perfect. A breast cancer may not be detected by mammogram because:

  • Some cancers are very difficult to see on the x-ray.
  • Some cancers, even though they are there, can’t be seen on the x-ray at all.
  • The person reading the x-ray may miss the cancer. This will happen occasionally, no matter how experienced the person reading the x-ray is. To reduce the risk of a cancer being missed, all mammograms are looked at by two people.

Cancer may develop between screenings

Women having screening can still be diagnosed with breast cancer between their appointments, even if their last mammogram was normal. This is known as an interval cancer.

Breast screening occasionally diagnoses a cancer that would never have needed treatment

It’s possible that a mammogram will find a breast cancer that would never have caused a problem during the woman’s lifetime. Unfortunately, it isn’t possible to tell the difference between cancers that will cause problems and those that won’t.

Research suggests that for every 200 women who have breast screening, one will have treatment that may not be needed. This means that most women who are diagnosed with breast cancer as a result of breast screening do need treatment, because their cancers would have gone on to develop and cause problems without treatment.

It can be difficult to decide whether to have breast screening. The doctors and nurses at your breast clinic can give you more information to help you make an informed decision.

As breast screening can’t pick up every cancer, you should see your GP if you have any unexplained changes in your breasts including lumps, pain and discharge from the nipples. You should see your GP even if you’re having regular breast screening and have recently had a normal mammogram.

There are many reasons for changes in breast tissue. Most of them are harmless, but you should always get your breasts checked as there is a small chance that the changes could be the first sign of cancer.

Back to Breast screening

The breasts

Breasts are made of fat, supportive (connective tissue) and glandular tissue that contains lobes (milk glands).

Breast awareness

Knowing what your breasts normally feel and look like can help you to notice any changes early.