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.