Some screening tests are used because they have been shown to be helpful both in finding cancers early and in decreasing the chance of dying from these cancers. Other tests are used because they have been shown to find cancer in some people; however, it has not been proven in clinical trials that use of these tests will decrease the risk of dying from cancer.
Scientists study screening tests to find those with the fewest risks and most benefits. Cancer screening trials also are meant to show whether early detection (finding cancer before it causes symptoms) decreases a person’s chance of dying from the disease. For some types of cancer, the chance of recovery is better if the disease is found and treated at an early stage.
Clinical trials that study cancer screening methods are taking place in many parts of the country. Information about ongoing clinical trials is available from the
A mammogram is an x-ray of the breast. This test may find tumors
that are too small to feel. A mammogram may also find ductal carcinoma in situ, abnormal cells in the lining of a breast duct, which may become invasive cancer in some women. The ability of a mammogram to find breast cancer may
depend on the size of the tumor, the density of the breast tissue, and the
skill of the radiologist. Mammograms are less likely to find breast tumors in women younger than 50 years than in older women. This may be because younger women have denser breast tissue that appears white on a mammogram. A tumor also appears white on a mammogram, which makes it hard to find.
A clinical breast exam is an exam of the breast by a doctor or other health professional. The doctor will carefully feel the breasts and under the arms for lumps or anything else that seems unusual.
It is important to know how your breasts usually look and feel. If you feel any lumps or notice any other changes, talk to your doctor.
If a lump or anything else that seems abnormal is found using one of these 2 tests, ultrasound may be used to learn more. Ultrasound is not used by itself as a screening test for breast cancer. This is a procedure in which high-energy sound waves (ultrasound) are bounced off internal tissues or organs and make echoes. The echoes form a picture of body tissues called a sonogram.
MRI is a procedure that uses a magnet, radio waves, and a computer to make a series of detailed pictures of areas inside the body. This procedure is also called nuclear magnetic resonance imaging (NMRI). MRI does not use any x-rays.
In women with a high inherited risk of breast cancer, screening trials of MRI breast scans have shown that MRI is more sensitive than mammography for finding breast tumors. It is common for MRI breast scan results to appear abnormal even though no cancer is present. Screening studies of breast MRI in women at high inherited risk are ongoing.
In women at average risk for breast cancer, MRI scans may be done to help with diagnosis. MRI may be used to:
Breast tissue sampling is taking cells from breast tissue to examine under a microscope. Abnormal cells in breast fluid have been linked to an increased risk of breast cancer in some studies. Scientists are studying whether breast tissue sampling can be used to find breast cancer at an early stage or predict the risk of developing breast cancer. Three methods of tissue sampling are under study:
Screening clinical trials are taking place in many parts of the country.
Information about ongoing clinical trials is available from the