Breast screening does not prevent breast cancer from developing. But regular breast screening using mammograms is the best way to find early-stage breast cancers. This means treatment may be more successful. Research trials show that women who have breast screening reduce their risk of dying from breast cancer by up to 20%, compared to those who do not.
But there are some possible disadvantages of having breast screening. We explain the main benefits and disadvantages below. This might help you decide if you want to have breast screening.
If you are finding it hard to decide whether to have breast screening, you can:
- contact your local breast screening unit. Staff at the unit can answer any questions you have, or give you more information to help you decide
- talk to your GP
- talk to our cancer support specialists on 0808 808 00 00.
If you decide not to have breast screening, contact your breast screening unit by letter or phone to tell them. If you change your mind, you can contact them to make a new appointment. Even if you do not go, they will still invite you for screening again 3 years later if you are of screening age.
If you do not want to be invited again, ask the screening unit or your GP to take your name off the system. If you change your mind and want them to put you back on, you can contact the screening unit.
Breast screening saves lives
Research shows breast screening programmes probably prevent around 1,300 women in the UK dying from breast cancer every year.
Most cancers found through breast screening are at an early stage. This means treatment is more likely to be successful. More than half of all breast cancers found through screening are very small. And 4 out of 5 (80%) have not spread to the lymph nodes. The lymph nodes in the armpit are one of the first places breast cancer may spread to.
If a breast cancer is found early and it is small, the surgeon can usually do breast-conserving surgery. This is when they remove the cancer and some surrounding tissue, instead of removing the whole breast. Radiotherapy is usually given after breast-conserving surgery. Around 4 out of 5 women diagnosed through breast screening (80%) have breast-conserving surgery.
Breast screening cannot prevent cancer
Breast screening only helps find a breast cancer that is already there. It cannot prevent breast cancer.
Having a mammogram can be uncomfortable
Many women find having a mammogram uncomfortable. Some women find it painful. This usually only lasts for a short time. But some women may find the area is tender for a few days afterwards.
You can take painkillers to help. Your doctor or nurse at the breast screening unit can also suggest what might help.
Having a mammogram involves x-rays
All x-rays use a small amount of radiation. This includes mammograms. The amount given during a mammogram is very small and unlikely to cause any harm. The radiation dose is kept as low as possible, while making sure it gives good-quality images.
The NHS England breast screening information says having mammograms every 3 years for 20 years very slightly increases the risk of cancer in your lifetime.
But the benefits of screening and finding breast cancer early are thought to outweigh the risks of having a mammogram.
If you are worried about the risks of radiation, talk to the staff at the breast screening unit.
Results may cause unnecessary worry
Mammograms can sometimes show an abnormal area in the breast that further tests show is not a cancer. This is called a false-positive result.
Waiting to get the results of these tests can be very worrying. Some women may still feel anxious, even if the doctor or nurse has told them they do not have breast cancer. You can talk to the nurse about any worries you have.
Mammograms sometimes need to be taken again
This happens after 1 or 2 mammograms in every 100 (1 or 2%). It can happen because:
- the mammogram has missed part of the breast tissue
- the x-ray picture is blurred
- there is a problem with the equipment, but this is rare.
Cancer may be diagnosed between screenings
Women having breast screening can still be diagnosed with breast cancer between their screening appointments. This can happen even if their last mammogram was normal. This is called an interval cancer. It can happen for the following reasons:
- Sometimes cancers are hard to see on a mammogram.
- The cancer may have been too small to be seen at that time.
- Occasionally, the person looking at the mammogram may miss the cancer. To reduce this risk, each mammogram is looked at by two specially trained members of staff.
If you notice any changes in the way your breasts look or feel, make an appointment to see your GP straight away. You should do this even if you have recently had a normal mammogram.
Breast screening may find cancer that might never have needed treatment
Some breast cancers diagnosed through breast screening may never grow any bigger or spread into surrounding breast tissue. Or they may grow so slowly that they would never have caused any problems.
All women who are diagnosed with breast cancer are offered treatment. This is because it is not possible to tell which cancers do not need treatment. Because of this, some women will have treatment for a cancer that may never have caused any problems. Doctors are trying to find out how to decide which cancers may not need treatment.
It is not clear how many women are treated for a cancer that might never have caused any problems. Current research suggests about 1 in 5 cancers diagnosed through screening (20%) would never have caused a problem.