Patient education: Breast cancer screening (The Basics)

What is breast cancer screening? — Breast cancer screening is a way in which doctors check the breasts for early signs of cancer in people who have no symptoms of breast cancer. The main test used to screen for breast cancer is a special kind of X-ray called a "mammogram."

The goal of breast cancer screening is to find cancer early, before it has a chance to grow, spread, or cause problems. Studies show that being screened for breast cancer lowers your chance of dying from the disease.

Who should be screened for breast cancer? — Different experts have different recommendations for breast cancer screening. Also, the recommendations for screening might be different for people at higher risk of getting breast cancer.

●Starting at the age of 40, it's important to talk to your doctor or nurse about the benefits and downsides of screening and decide, with your doctor's or nurse's help, whether to get screening and when.

●Some people who are at high risk of breast cancer might need to begin screening before age 40. For example, this might be the case if you have certain genes that increase your risk of breast cancer (such as "BRCA" genes).

●Regular screening with mammograms generally continues through age 74 years. Some people choose to continue getting regular mammograms after this if they are healthy and expected to live for at least 10 more years.

What are the benefits of being screened for breast cancer? — The main benefit of screening is that it helps doctors find cancer early, when it might be easier to treat. This lowers the chances of dying from breast cancer.

What are the downsides to being screened for breast cancer? — The downsides include:

●False positives – Mammograms sometimes give "false-positive" results. This means that the results suggest that you might have cancer when you actually do not. This can lead to unneeded worry and more tests, including a biopsy in some cases, which can be painful. False-positive results are more likely to happen in people younger than 50 than in older people.

●Finding cancer that would not have needed treatment – Sometimes, mammograms find cancer that would never have affected your health. This can be a problem because treating these cancers does not have any benefit, and can cause harm. For example, you could get surgery, radiation treatment, or chemotherapy to treat a cancer that never would have caused problems if it hadn't been found. There is no way to know which cancers found by screening will lead to problems, and which won't.

●Radiation exposure – Like all X-rays, mammograms expose you to some radiation. But studies show that the number of lives saved by finding cancer early greatly outweighs the very small risks that come from this radiation exposure.

What happens during a mammogram? — During a mammogram, your breasts will be X-rayed 1 at a time. Each breast is typically X-rayed twice, once from the top down and once from side-to-side. This is so the radiologist can get a good look at all the tissue. To make the breast tissue easier to see, a nurse or technician will flatten each breast between 2 panels. This can be uncomfortable, but it lasts only a few seconds.

Your X-rays will be reviewed by a doctor called a radiologist. If they are able to do this right away, you might get the results the same day. If not, you should get your results within 30 days.

What if my mammogram is abnormal? — If your mammogram is abnormal, try not to panic. In 9 out of 10 cases, an abnormal mammogram turns out not to be breast cancer. You will need more tests to find out what's going on.

●If the doctor thinks that your abnormal result is probably not due to cancer, they might suggest another mammogram in 6 months. In other cases, they will do more tests. This could be because they need to get a better view of part of your breast, or because they think that the abnormal result might be due to cancer.

●Other tests could include a more detailed mammogram, which involves taking more X-rays to get a better view, or an ultrasound of the breast to check something seen on the mammogram. An ultrasound or MRI might also be suggested if your mammogram shows very dense breasts that can make a mammogram harder to read.

●If these tests show anything concerning, your doctor or nurse will probably order a biopsy. During a biopsy, a doctor takes a sample of breast tissue and sends it to the lab to be checked for cancer. This is most often done with a needle during a mammogram or ultrasound. But in some cases, biopsies involve a small surgery.

What about breast exams? — Many experts no longer believe that breast exams by a doctor or nurse are helpful for people who have no breast symptoms. Most lumps that are found when a doctor examines the breast are not actually cancer. Also, studies have not found that doing both a breast exam and mammogram is better than doing a mammogram alone.

Some people want to do exams on their own breasts. No study has shown that breast self-exams lower the risk of dying from breast cancer, and most experts do not encourage self-exams. Some experts encourage something called "breast self-awareness." This involves learning about your personal risk of breast cancer, what your breasts look and feel like normally, and what to do if you do notice a change in your breast. If you notice any changes in your breasts, talk to your doctor or nurse.

Can I have a breast MRI instead of a mammogram? — Screening breast MRIs are not for everyone. Compared with mammograms, breast MRIs give more "false positives" and sometimes lead to unneeded biopsies. Still, breast MRIs are sometimes used in people who have a high risk of breast cancer. MRIs don't replace mammograms. They are used along with mammograms for people who need them.

How often should I have a mammogram? — It is not clear what the best schedule for screening is. Many experts suggest mammograms every 2 years for most people, while others suggest mammograms every year. The schedule screening might also be different if you have a high risk of breast cancer. Talk with your doctor about how often you should have a mammogram based on your risk as well as your preferences.

Can I have screening after I've gotten the COVID-19 vaccine? — Yes, but your doctor might recommend not scheduling them close together. Some people have had temporary swelling of lymph nodes in the armpit area after getting certain COVID-19 vaccines. In some cases, this can make it harder for doctors to interpret your mammogram. If you're not sure when to schedule your mammogram, talk to your doctor or nurse. They can help you make this decision based on your situation.

More on this topic

Patient education: Breast cancer (The Basics)
Patient education: Cancer screening (The Basics)
Patient education: Common breast problems (The Basics)
Patient education: Breast biopsy (The Basics)
Patient education: Sentinel lymph node biopsy for breast cancer (The Basics)
Patient education: Mammogram (The Basics)
Patient education: Breast ultrasound (The Basics)
Patient education: MRI scan (The Basics)

Patient education: Breast cancer guide to diagnosis and treatment (Beyond the Basics)
Patient education: Breast cancer screening (Beyond the Basics)
Patient education: Factors that affect breast cancer risk in women (Beyond the Basics)
Patient education: Common breast problems (Beyond the Basics)