After your breasts have been X-rayed, the mammogram will be checked for any abnormalities. About one in 25 women will be called back for further assessment.
Being called back doesn't mean you definitely have cancer. The first mammogram may have been unclear.
About one in four women who are called back for further assessment are diagnosed with breast cancer.
You will receive a letter with your breast screening results within two weeks of your appointment. The results will also be sent to your GP.
Most women will have a satisfactory result
In about 96 out of every 100 women screened, the mammogram will show no sign of cancer. This is a satisfactory result.
Remember that cancer can still develop between mammograms, so tell your GP straight away if you notice any breast changes. Read about the symptoms of breast cancer.
Some women will need more tests because they have an abnormal result
The results letter may say you need more tests because the mammogram looks abnormal. About four in every 100 women are asked to come back for more tests after screening.
Out of these four women, one will be found to have cancer. The rest will not have cancer and will go back to having screening invitations every three years.
If you are called back for more tests, you may have a breast examination, more mammograms and ultrasounds. You may also have a biopsy, which is when a small sample is take from your breast with a needle to be checked under a microscope. You will usually get your results within a week.
Occasionally, women will need another mammogram before they get their result
Sometimes technical problems mean that the mammogram is not clear enough to read. If this happens, you will be asked to have another mammogram to get a clearer picture of your breast.
If you're found to have breast cancer...
If you're found to have breast cancer, it could be either non-invasive or invasive.
Non-invasive breast cancer
About one in five women diagnosed with breast cancer through screening will have non-invasive cancer. This means there are cancer cells in the breast, but they are only found inside the milk ducts (tubes) and have not spread any further. This is also called ductal carcinoma in situ (DCIS).
In some women, the cancer cells stay inside the ducts. But in others, they will grow into (invade) the surrounding breast in the future.
Doctors can't tell whether non-invasive breast cancers will grow into the surrounding breast or not.
Invasive breast cancer
About four in five women diagnosed with breast cancer through screening will have invasive cancer. This is cancer that has grown out of the milk ducts and into the surrounding breast. Most invasive breast cancers will spread to other parts of the body if left untreated.
Read about the treatment of both invasive and non-invasive breast cancer.