Ultrasound machine emitting waves

What Tests Are Used to Diagnose Breast Cancer?

Before or during diagnosis, there are several tests which may be used in evaluating potential breast cancer.


Mammography is the use of x-rays to take pictures of the breast tissue. During a mammogram, the breast is compressed between two plates to spread out the tissue for a clearer image. Diagnostic mammograms are used when someone is having a symptom that may be indicative of breast cancer, such as a lump, changes in the skin of the breast, nipple discharge, or change in the size or shape of a breast. Diagnostic mammograms may also be used if an abnormality was detected in a screening mammogram.1


Ultrasound is an imaging technique that uses sound waves to produce a picture. Breast ultrasound may be used to further evaluate a lump found by the patient or her doctor or to evaluate an abnormal finding from a mammogram. Ultrasound can help differentiate between a fluid-filled lump (such as a harmless cyst) or a solid lump. If the lump is determined to be solid, additional tests (like a biopsy) may be needed, as an ultrasound cannot distinguish between a cancerous solid lump and a non-cancerous solid lump.2,3

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Magnetic Resonance Imaging (MRI)

MRI is an imaging test that uses powerful magnets and radio waves to generate detailed images of the structures within the breast. An MRI may be used on the breast to further evaluate abnormalities found on a mammogram, to screen women who are at high risk for breast cancer, or to determine the extent of a diagnosed breast cancer.4


A biopsy is a procedure in which a sample of tissue is removed from the breast to examine it for cancerous (malignant) cells under a microscope. There are several different types of biopsies that may be performed on the breast, such as fine needle aspiration biopsy, core needle biopsy, stereotactic biopsy, ultrasound-guided biopsy, MRI-guided biopsy, surgical biopsy, and/or a lymph node biopsy.5

Cancer genomics

Genomic testing looks at the particular mutations that occur in cancerous tissue. Genomic testing is done on a sample of a tumor and can be helpful in determining the risk of recurrence (the cancer coming back) or which treatments might be most effective.6

Genetic testing

Genetic testing can identify certain mutations that someone may be born with that may increase their risk of developing cancer. It may also be used in young women diagnosed with breast cancer, or those with a strong family history of the disease, to help guide potential treatment decisions.7

Breast cancer staging

Breast cancer staging describes the extent of the disease, including the size of the tumor, any lymph node involvement, and whether the breast cancer has spread to distant parts of the body (metastasis). The staging of breast cancer helps to determine the recommended treatment. Staging is based on the tumor, node, and metastasis (TNM) system, which describes the size of the tumor, lymph node involvement, and whether there are distant metastases (the cancer has spread to other organs).8