by Dr. Sadir Al Rawi, Director of Surgical Oncology Services
What is breast cancer screening
Cancer screening involves testing apparently healthy people for signs that could show that a cancer is developing.
Breast cancer screening uses a test called mammography which involves taking X-rays of the breasts. Screening can help to find breast cancers early, when they are too small to see or feel. These tiny breast cancers are usually easier to treat than larger ones.
Who has breast cancer screening
Breast Screening Program invites all women aged between 40 and 70 for screening every 1 years.
If you are younger than 40, your risk of breast cancer is generally very low. Mammograms are more difficult to read in younger women because their breast tissue is denser. So the patterns on the mammogram don’t show up as well. There is little evidence to show that regular mammograms for women below the screening age would reduce deaths from breast cancer.
Tests used in breast screening
Breast screening takes 2 X-rays of each breast. The X-rays are called mammograms.
You have one mammogram from above and one from the side.
After the test
You should get your results within 2 weeks. The radiographer can tell you when to expect yours. Most women have a normal reading.
If the results are not clear
If the X-ray is not clear enough or shows any abnormal areas, the clinic staff will call you back for more tests. You may need to have the X-rays taken again.
If you are called back
Around 4 out of 100 women (4%) are called back and this can make them feel very anxious. If you are called back because your mammogram showed an abnormal area, you may have a magnified mammogram. This can show up particular areas of the breasts more clearly. They show the borders of any lump or thickened area and can also show up areas of calcium (calcification).
Only around 1 in 5 women called back will turn out to have cancer. So out of every 5 women called back, 4 will be fine.
Overall, the breast screening programme finds cancer in about 8 out of every 1,000 women having screening.
Benefits of breast screening
Breast cancers found by screening are generally at an early stage. Very early breast cancers are usually easier to treat, may need less treatment, and are more likely to be cured. The current evidence suggests that breast screening reduces the number of deaths from breast cancer
Women who are diagnosed with breast cancer at the earliest possible stage have a 9 in 10 chance (90%) of surviving for at least 5 years after diagnosis.
Harms of breast screening
Although breast cancer screening can find many cancers early it is not perfect. There are some risks.
False positives and false negative results
Screening doesn’t always find a cancer that is there. So some people with breast cancer will be missed. This is called a false negative result.
In some women, the test picks up something even though they don’t have breast cancer. This is called a false positive result and can lead to anxiety and further tests such as a breast biopsy.
Overdiagnosis and overtreatment
As well as finding cancers that need treating, screening can also pick up some breast cancers that will not cause any problems in a woman’s lifetime. At the moment it is not possible for doctors or patients to be certain whether a breast cancer will grow quickly and needs treating, or will grow slowly or not at all. So, almost all women with breast cancer have surgery to remove the cancer and many also have radiotherapy, hormone therapy and chemotherapy. For some women the treatment is unnecessary but at the moment doctors can’t tell who needs treatment and who doesn’t.
Screening can also pick up changes in the lining of the breast ducts called ductal carcinoma in situ. It is not possible to tell whether DCIS will develop into a cancer or not. So, many women with DCIS will also have breast cancer treatments.
Some women who go for breast screening will have treatment for a breast cancer or DCIS that never would have caused them any harm. This is called overdiagnosis or overtreatment.
Exposure to radiation
Each mammogram exposes a woman to small amounts of radiation from the X-rays. But the amount of radiation is very small. For every 10,000 women who have regular yearly breast screening between the ages of 40 and 73, experts estimate that there will be between 3 and 6 extra breast cancers caused by radiation.
Screening for women at higher risk
Women at higher than average risk of breast cancer due to a family history or an inherited faulty gene can have screening from a younger age. If you think you might be at increased risk, speak to your GP. They can refer you to a genetic specialist, who will be able to assess your risk. Not everyone with a family history of cancer is at increased risk themselves.
If you have a gene mutation
If you have had tests that show you have a change in a gene (mutation) known to increase the risk of breast cancer, the recommendations are slightly different. Its recommend yearly MRI scans from
- Age 20 for women with a TP53 mutation
- Age 30 for women with a BRCA1 or BRCA2 mutation
Should I go for breast screening?
It’s important that you have access to enough information about the benefits and harms of breast screening to make the decision about whether to go.
Breast cancer awareness
Even if you are having mammograms every 1 year it is important to make sure that you know how your breasts normally look and feel. Many breast cancers are still found by women themselves. Cancers can develop between mammograms. This is known as an interval cancer. Mammograms can also miss some cancers.