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As well as helping to save lives|, breast screening has some potential disadvantages. These are described here to help you decide whether to go for screening.
It only helps to find a breast cancer if it is already there.
Many women find having a mammography uncomfortable or even painful, but this is normally just for a short time. However, some women may find that the pain or soreness lasts for a few days.
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. Therefore, the radiation risk associated with having a mammogram every three years is considered to be far outweighed by the benefits of detecting a breast cancer at an early stage, when it is more likely to be curable.
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. You can find detailed information about the radiation risk of breast screening from the NHS website|. You can also telephone the NHS Response Line on 08701 555 455.
Mammograms can sometimes show an abnormal area in the breast that is later found not to be a cancer when further tests are carried out. This is known as a false-positive result. Waiting to get results of further tests can be a very worrying time, and some women may continue to feel anxious even after they’ve been told they don’t have breast cancer (a negative result).
About 1 in 20 women who have breast screening will have an abnormal result and be asked to go for further tests. The tests may include more mammograms, ultrasound scans or biopsies of the breast tissue, which can cause pain or scarring. Most of the women (around 7 in 8) asked back for further tests won’t have breast cancer.
One or two mammograms in every 100 have to be taken again because:
Although mammography is the most effective and reliable way of detecting breast cancer early, it is not perfect. A breast cancer may not be detected by mammogram because:
Women having three-yearly breast screening may be diagnosed with breast cancer in the time between their screening appointments, even if they had a normal result after their last mammogram. This is known as an interval cancer.
If an interval cancer is diagnosed, the mammography films taken at the time of diagnosis will be compared to the previous mammograms. Women diagnosed with an interval cancer will always have the results of this review discussed with them. Research shows that the outlook and cure rates for women with interval cancers are better than for women who have never attended screening.
It is possible that a mammogram could find a breast cancer that would never have caused a problem during the woman's lifetime. Unfortunately, it is not possible to tell the difference between cancers that do cause problems and those that will not.
Research suggests that for every 200 women who have breast screening, one will have treatment that may not be needed. About 1 in 8 of all breast cancers detected would not have caused problems. 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 the 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 are 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 them checked as there is a small chance that the changes could be the first sign of cancer.
Content last reviewed: 1 January 2011
Next planned review: 2013
For answers, support or just a chat, call the Macmillan Support Line free (Monday to Friday, 9am-8pm)
If you have any questions about cancer, need support or just want someone to talk to, ask Macmillan.
It is up to you whether you go for breast screening. It could help to find out the facts, which you can do by reading our cancer information team's blog in our online community. There, you can talk over your options with people who understand.
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© Macmillan Cancer Support 2013
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