Breast cancer is a disease in which malignant (cancer) cells form in the tissues of the breast.
The breast is made up of lobes and ducts. Each breast has 15 to 20 sections called lobes, which have many smaller sections called lobules. Lobules end in dozens of tiny bulbs that can produce milk. The lobes, lobules, and bulbs are linked by thin tubes called ducts.
Anatomy of the female breast. The nipple and areola are shown on the outside of the breast. The lymph nodes, lobes, lobules, ducts, and other parts of the inside of the breast are also shown.
Tests are used to screen for different types of cancer when a person does not have symptoms.
Mammography is the most common screening test for breast cancer.
Magnetic resonance imaging (MRI) may be used to screen women who have a high risk of breast cancer.
Whether a woman should be screened for breast cancer and the screening test to use depends on certain factors.
Other screening tests have been or are being studied in clinical trials.
Breast Exam
Thermography
Tissue sampling
Screening tests for breast cancer are being studied in clinical trials.
Breast cancer is the second leading cause of death from cancer in Indian women
Women in the United States get breast cancer more than any other type of cancer except for skin cancer.
Breast cancer is more likely to occur as a woman ages. It occurs more often in White women than in Black women, but Black women die from breast cancer more often than White women.
Breast cancer rarely occurs in men. Because men with breast cancer usually have a lump that can be felt, screening tests are not likely to be helpful.
Tests are used to screen for different types of cancer when a person does not have symptoms
Scientists study screening tests to find those with the fewest harms and most benefits. Cancer screening trials also are meant to show whether early detection (finding cancer before it causes symptoms) helps a person live longer or 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.
Mammography is the most common screening test for breast cancer.
A mammogram is a picture of the inside of the breast. Mammography may find tumors that are too small to feel. It may also find ductal carcinoma in situ (DCIS). In DCIS, abnormal cells line the breast duct, and in some women may become invasive cancer.
There are different types of mammograms:
- Film mammography is an x-ray picture of the breast.
- Digital mammography (DM) is a computer picture of the breast.
- Digital breast tomosynthesis (DBT) uses x-rays to take a series of pictures of the breast from many different angles. A computer is used to make 3-D pictures of the breast from these x-rays.
- 2-dimensional mammography (S2D) uses x-rays to take pictures of the inside of the breast, usually from two different angles. A computer or x-ray film is used to make 2-D pictures of the breast
Digital breast tomosynthesis (DBT) was approved by the U.S. Food and Drug Administration (FDA) in 2018 and is now used in 3 out of 4 facilities. One recent study found that 2-dimensional mammography (S2D) combined with DBT improved tumor detection rates and lowered mammogram callbacks, radiation dose, and overall costs. More studies are being done to compare different types of breast cancer screening.
Mammography is less likely to find breast tumors in women with dense breast tissue. Because both tumors and dense breast tissue appear white on a mammogram, it can be harder to find a tumor when there is dense breast tissue. Younger women are more likely to have dense breast tissue. For more information, see Dense Breasts: Answers to Commonly Asked Questions.
Mammography. The breast is pressed between two plates. X-rays are used to take pictures of breast tissue.
Many factors affect whether mammography is able to detect (find) breast cancer:
- The age and weight of the patient.
- The size and type of tumor.
- Where the tumor has formed in the breast.
- How sensitive the breast tissue is to hormones.
- How dense the breast tissue is.
- The timing of the mammography within the woman’s menstrual cycle.
- The quality of the mammogram picture.
- The skill of the radiologist in reading the mammogram.
Women aged 50 to 69 years who have screening mammograms have a lower chance of dying from breast cancer than women who do not have screening mammograms.
Fewer women are dying of breast cancer in the United States, but it is not known whether the lower risk of dying is because the cancer was found early by screening or whether the treatments were better.
Magnetic resonance imaging (MRI) may be used to screen women who have a high risk of breast cancer.
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 and the woman is not exposed to radiation.
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Other screening tests have been or are being studied in clinical trials.
Studies have been done to find out if the following breast cancer screening tests are useful in finding breast cancer or helping women with breast cancer live longer.
Breast Exam
A clinical breast exam is an exam of the breast by a doctor or other health professional. He or she will carefully feel the breasts and under the arms for lumps or anything else that seems unusual. It is not known if having clinical breast exams decreases the chance of dying from breast cancer.
Breast self-exams may be done by women or men to check their breasts for lumps or other changes. If you feel any lumps or notice any other changes in your breasts, talk to your doctor. Doing regular breast self-exams has not been shown to decrease the chance of dying from breast cancer.
Thermography
Thermography is a procedure in which a special camera that senses heat is used to record the temperature of the skin that covers the breasts. Tumors can cause temperature changes that may show up on the thermogram.
There have been no randomized clinical trials of thermography to find out how well it detects breast cancer or the harms of the procedure.
Tissue sampling
Breast tissue sampling is taking cells from breast tissue to check under a microscope. Breast tissue sampling as a screening test has not been shown to decrease the risk of dying from breast cancer.
Screening tests for breast cancer are being studied in clinical trials.
Information about clinical trials supported by NCI can be found on NCI’s clinical trials search webpage. Clinical trials supported by other organizations can be found on the ClinicalTrials.gov website.