The risks of breast cancer screening tests include the following. - Finding breast cancer may not improve health or help a woman live longer. Screening may not help you if you have fast-growing breast cancer or if it has already spread to other places in your body. Also, some breast cancers found on a screening mammogram may never cause symptoms or become life-threatening. Finding these cancers is called overdiagnosis.  Finding breast cancer may not improve health or help a woman live longer. Screening may not help you if you have fast-growing breast cancer or if it has already spread to other places in your body. Also, some breast cancers found on a screening mammogram may never cause symptoms or become life-threatening. Finding these cancers is called overdiagnosis. - False-negative test results can occur. Screening test results may appear to be normal even though breast cancer is present. A woman who receives a false-negative test result (one that shows there is no cancer when there really is) may delay seeking medical care even if she has symptoms. False-negative test results can occur. Screening test results may appear to be normal even though breast cancer is present. A woman who receives a false-negative test result (one that shows there is no cancer when there really is) may delay seeking medical care even if she has symptoms. - False-positive test results can occur. Screening test results may appear to be abnormal even though no cancer is present. A false-positive test result (one that shows there is cancer when there really isnt) is usually followed by more tests (such as biopsy), which also have risks.  False-positive test results can occur. Screening test results may appear to be abnormal even though no cancer is present. A false-positive test result (one that shows there is cancer when there really isnt) is usually followed by more tests (such as biopsy), which also have risks. - Anxiety from additional testing may result from false positive results. In one study, women who had a false-positive screening mammogram followed by more testing reported feeling anxiety 3 months later, even though cancer was not diagnosed. However, several studies show that women who feel anxiety after false-positive test results are more likely to schedule regular breast screening exams in the future. Anxiety from additional testing may result from false positive results. In one study, women who had a false-positive screening mammogram followed by more testing reported feeling anxiety 3 months later, even though cancer was not diagnosed. However, several studies show that women who feel anxiety after false-positive test results are more likely to schedule regular breast screening exams in the future. - Mammograms expose the breast to radiation. Being exposed to radiation is a risk factor for breast cancer. The risk of breast cancer from radiation exposure is higher in women who received radiation before age 30 and at high doses. For women older than 40 years, the benefits of an annual screening mammogram may be greater than the risks from radiation exposure.  Mammograms expose the breast to radiation. Being exposed to radiation is a risk factor for breast cancer. The risk of breast cancer from radiation exposure is higher in women who received radiation before age 30 and at high doses. For women older than 40 years, the benefits of an annual screening mammogram may be greater than the risks from radiation exposure. - There may be pain or discomfort during a mammogram. During a mammogram, the breast is placed between 2 plates that are pressed together. Pressing the breast helps to get a better x-ray of the breast. Some women have pain or discomfort during a mammogram.  There may be pain or discomfort during a mammogram. During a mammogram, the breast is placed between 2 plates that are pressed together. Pressing the breast helps to get a better x-ray of the breast. Some women have pain or discomfort during a mammogram. Some women worry about radiation exposure, but the risk of any harm from a mammogram is actually quite small. The doses of radiation used are very low and considered safe. The exact amount of radiation used during a mammogram will depend on several factors. For instance, breasts that are large or dense will require higher doses to get a clear image. Learn more about the risks of breast cancer screening.