Diagnosing breast cancer

This page was reviewed under our medical and editorial policy by

Maurie Markman, MD, President, Medicine & Science.

This page was updated on May 5, 2022.

How is breast cancer diagnosed? 

Many doctors have the training and experience to diagnose and treat many breast cancer types, from triple-negative, inflammatory and metastatic to luminal, HER2-positive or others. 

In diagnosing inflammatory breast cancer and other breast cancer types and staging the disease, cancer experts use sophisticated diagnostic tools to locate the tumor and determine whether it has spread. Your care team may also test the tumor for specific genetic abnormalities or hormone sensitivities that suggest it may respond to targeted therapy or other personalized treatments. 

If a lumpectomy, breast-conserving surgery or mastectomy is part of your breast cancer treatment plan, different cancer care providers may offer microsurgical and other reconstruction techniques. Further, your oncologist may help determine if you are the right fit or an ongoing clinical trial. 

Tools used for diagnosing breast cancer include:

Lab tests

In some cases, certain types of lab tests, called genomic tests, are used to learn more about the genetic makeup of breast cancer cells. Genomic tests can help your doctors examine specific genes and proteins in the cancer cells and develop a treatment plan that is specifically geared to disrupt and fight the specific cancer. The information can also help you and your doctors understand the risk of recurrence of your type of cancer.

These genomic tests require a sample of the tumor that has been removed during biopsy or surgery. Then, specialists examine the tumor sample and its genetic profile in a laboratory. Typically, if you need to have the genetics of your tumor tested, you will have already undergone biopsy or surgery and will not need an additional procedure to obtain the sample.  

Advance genomic testing: Genomic testing examines a tumor on a cellular level to look for the DNA alterations that are driving the growth of cancer. By identifying the mutations that occur in a cancer cell's genome, doctors can better understand what caused the tumor and tailor treatment based on these findings.

Oncotype DX®: The Oncotype DX test (also called the 21-gene test) is used to determine whether breast cancer chemotherapy is likely to benefit women with early-stage breast cancer. This lab test also helps your cancer care team to know the likelihood of disease recurrence. With this information, you and your team are better able to make more informed decisions about your breast cancer treatment. 

MammaPrint® and Blueprint®: The MammaPrint and BluePrint genomic lab tests are used to decode a breast tumor's unique traits to help us craft a targeted treatment plan specific to each patient’s individual needs. MammaPrint is used to determine the risk that a patient’s cancer will return. BluePrint is used to determine which of the tumor’s mutations are dictating the cancer’s behavior. When used with the MammaPrint assay, BluePrint narrowly defines each tumor into a subtype classification, affording your doctor a clearer picture for a more precise treatment strategy.


If your doctor suspects you may have breast cancer, a biopsy can help confirm or rule out the diagnosis. A biopsy is a procedure that takes a sample of cells or tissue from the suspicious breast area. The cells are then examined in a laboratory to see if they are cancerous. 

Some common biopsies used to help doctors diagnose breast cancer include fine-needle aspiration biopsy, which uses a small needle; core needle biopsy, which uses a larger needle; MRI-guided biopsy; or surgical biopsy, in which all or part of a lump is removed and checked for cancer. Fine-needle aspiration and core needle biopsies may be performed using certain imaging tests, such as ultrasound, breast MRI, mammography or CT scan. 

A sentinel lymph node biopsy may first be performed to determine whether cancer has spread to the lymph glands under the arm. A radioactive substance and/or a dye is injected directly under the skin of the breast. The first set of lymph nodes are then removed and reviewed by a pathologist to check for the presence of cancer cells. 

The type of biopsy used will depend on several factors, including the size of the suspected tumor is, where it is in the breast and if there is more than one. Your medical history and your personal preferences will also play a role in the decision.  

Biopsies that use a needle are outpatient procedures and are typically performed using imaging guidance. Some needle biopsies may be performed in your doctor’s office. You’ll likely receive local anesthesia to numb the breast, but you’ll be awake during the process. During the procedure, a needle is placed through the skin into the suspicious area, and fluid or tissue is suctioned into a syringe. Core needle biopsies are used more often because they remove more tissue compared to a fine needle aspiration biopsy.  

Surgical biopsies involve making an incision in the skin on the breast to remove tissue. These biopsies are more likely to be performed in a hospital’s outpatient department. You’ll receive sedative drugs to make you calm and drowsy during the procedure and a local anesthetic to numb your breast area. Alternatively, you may go under general anesthesia to stay in a deep sleep during the procedure. Stitches and a clean dressing are then applied to the area after the procedure to help with wound healing on the skin.

Metastatic cancer detection

Interventional radiologists, physicians who specialize in minimally invasive, targeted treatments, use specific imaging and radio wave tests to detect metastasis in different parts of the body. For example, they may use microwave ablation for breast cancer patients with metastasis to the liver. Microwave ablation is a procedure that utilizes small devices called antenna to send heat toward cancerous cells.

Other types of imaging tests, such as PET scan or MRI may be used to determine if cancer has spread to other locations in the body. 

Imaging tests

Various imaging procedures are used to diagnose breast cancer, including:

Ultrasound: This imaging test detects even slight abnormalities in dense breasts and can help determine whether a lump is a cyst (sac containing fluid) or a solid mass. Ultrasound may also be used to locate the position of a tumor in order to guide the doctor during a biopsy or aspiration procedure. For example, in some cases, surgical oncologists will use an intraoperative ultrasound during a lumpectomy to mark out the boundaries of the tumor prior to its removal.  

Before an ultrasound begins, a clear gel will be applied to the breast. Then, a small probe will be placed on top of the gel and moved over the breast area. The probe creates a picture of the inside of the breast and sends it to a computer screen. If there is a suspicious area or lump in the breast, the ultrasound images can help your doctor take a closer look at the area. It is not a painful procedure, but the pressure of the probe may feel uncomfortable. It may be done and performed in your doctor’s office. 

Mammography: Full-field digital mammography acquires sharp, digital images of the breasts with similar radiation exposure to traditional mammography. Once the digital images are received and transmitted to a high-tech, digital mammography workstation, a radiologist analyzes the images to determine the location and extent of the disease. 

Mammograms take around 20 minutes to complete. Before the test begins, you will receive a wrap gown to cover your upper body, as you will need to undress above the waist. Mammograms are performed by a mammographer—someone who is trained to operate the X-ray machine. The machine has two plates that compress or flatten the breast to take a better picture. Once you are ready to start, the mammographer will place your breast between the plates. Then, the upper plate will be lowered on top of your breast. Your breast will be compressed for a few seconds while a picture is taken. After the first picture, your breast will be repositioned, and the process will be repeated to get images of the whole breast from different angles. Each time the breast is compressed, you may feel some discomfort or even pain. However, each compression only lasts a few seconds.

MRI (magnetic resonance imaging): With this technology, radiofrequency waves create detailed cross-sectional images of the breasts. An MRI may help identify breast tumors in addition to those detected by a mammogram. You can get an MRI scan at a hospital or a clinic. You’ll likely change into a hospital gown before the test and remove any metal objects, such as jewelry or hair clips, from your body. During the test, you’ll be lying on your stomach on a table while your breasts hang down into an opening. The table will then slide into a narrow tube where the scan will be taken. You will need to stay very still while the images are being made. The test is painless and may take up to 60 minutes.

MRI-guided breast biopsy: With this minimally invasive, image-guided procedure, radiologists use MRI technology and targeting software to locate and remove cells from a suspicious area in the breast for diagnosis and treatment planning. 

PET/CT scan: This advanced nuclear imaging technique combines positron emission tomography (PET) and computed tomography (CT) into one machine. A PET/CT scan reveals information about both the structure and function of cells and tissues in the body during a single imaging session.   

Before a PET/CT scan, an IV that injects a small amount of a radioactive substance will be placed into one of your veins. This substance is often called a “tracer,” because it helps reveal cancer in the body. The PET scan shows where the tracer is concentrated (and thus where the cancer is likely to be), while the CT scan takes X-ray images of your body from different angles. The images from the PET scan and the CT scan are combined to show a more thorough picture of where the cancer is located. 

The radioactive substance takes around 30 to 90 minutes to spread throughout the body. You may need to drink a contrast liquid (or you may receive it through an IV) to help give the images more definition. Right before the test, you’ll be asked to go to the bathroom to empty your bladder.  

The scan is painless and only takes around 30 minutes, but the entire appointment may take up to 3 hours, considering the time it takes for the tracer to absorb.   

Bone scan: This test may reveal whether breast cancer has spread to the bone. By capturing images of bones on a computer, bone scans may reveal important information, such as the location of the bone metastasis.

A bone scan is similar to a PET scan in that it starts with an injection of a radioactive substance (tracer) that helps highlight if and where cancer is located. Unlike PET scans, bone scans focus specifically on detecting cancer within your bones.

Once your bones have absorbed the substance, you will lie on your back underneath a large scanning camera that moves around your body, taking pictures of where the tracer is concentrated. It takes between one to four hours for your bones to absorb the tracer, and a whole-body scan takes around one hour. You will need to hold still for the entire scan, but it isn’t painful.  

Digital breast tomosynthesis: Tomosynthesis is similar to a standard mammogram in that it uses X-ray technology and applies the same amount of pressure to the breast. But rather than providing two views—from top to bottom and side to side—the 3-D approach captures multiple views from a variety of angles in seconds.

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