Screening for breast cancer in women of average risk can include a combination of these:

• Breast self-awareness. In the past, a breast self-exam was recommended. The exam was a precise method of examining your breasts, about once a month. Most medical organizations now advise breast self-awareness instead. This means having a sense of what is normal for your breasts so that you can notice even small changes and report them to a healthcare provider right away.

• Clinical breast exam (CBE). The American Congress of Obstetricians and Gynecologists (ACOG) advises CBEs every 1 to 3 years for all women in their 20s and 30s. ACOG advises CBEs every year for women 40 and older. Other medical organizations disagree that there is enough evidence to assess the value of CBEs for women age 40 and older. Women should talk with their doctor about their risk factors and make a decision about whether to have a CBE.

• Mammography. A mammogram is a kind of X-ray used to help find breast tumors before symptoms of cancer appear. During the test, your breast is placed between 2 metal or plastic plates that flatten and spread the tissue. Very low levels of radiation are used to take a picture of the inside of your breast. Many facilities have digital mammography. This displays results on a computer instead of on film. The test can be uncomfortable, but it only lasts a few moments. 

• Breast MRI. An MRI uses magnets, radio waves, and a computer to make detailed pictures of the inside of the breast. Before the MRI, you may be injected with a contrast dye. This helps to better outline the breast tissue and possible tumors. MRI is only used to screen women who are at a high risk for breast cancer.

These screening methods can improve your chances of catching cancer early. Women at high risk for breast cancer may be advised to start breast cancer screening at a younger age, and have an MRI in addition to a mammogram. For some women with dense breast tissue, ultrasound may be done in addition to a mammogram.

The benefits and limits of a mammogram vary. They’re based on factors such as age and personal risk. Experts have different advice for who should have mammograms.

• The U.S. Preventive Task Force (USPSTF) advises screening every 2 years for women age 50 to 74, with the choice to start getting mammograms every 2 years starting at age 40.

• The American Cancer Society advises yearly screening for all women ages 45 to 54, then a choice of screening every 2 years or every 1 year for women age 55 and older. Women ages 40 to 45 have the option to start screening.

• The American Congress of Obstetricians and Gynecologists advises that starting at age 40, women should have the option of starting to get mammograms every 1 or 2 years. All women should start at age 50. Mammograms every 1 or 2 years should be done until age 75. At that time a woman should talk to her doctor about whether to continue screening.

All women should talk with their doctor about their personal risk factors before making a decision about when to start and how often to get a mammogram.

A mammogram detects tumors and calcium deposits in the breast. Most calcium deposits are not cancer. But a cluster of very tiny specks of calcium (microcalcifications) can be an early sign of breast cancer. If your mammogram shows anything abnormal, you may need more tests.

A mammogram is the best way to find breast cancer early. But it may not always detect cancer. And in some cases, it may find an abnormality that turns out not to be cancer. This is called a false positive.