A biopsy is a procedure that allows your healthcare team to remove a small amount of tissue from your breast.

To check for breast cancer, a biopsy can be performed on breast tissue, lymph nodes (small immune system organs where breast cancer can sometimes spread), or in another part of the body if cancer is suspected there.

The removed tissue is then sent to a lab and examined by a pathologist, a doctor who specializes in diagnosing disease. The pathologist looks at the sample of your tissue under a microscope to see if it has any cancer cells.

Your pathologist reviews all the tissue samples from your biopsy, makes a diagnosis, and then creates a pathology report. After the final diagnosis, usually within a few days, the report will be available to the doctor who performed your biopsy. It is that doctor who often reviews the results with you.

Getting a biopsy doesn’t mean you will be diagnosed with breast cancer. Most people who have a biopsy do not have cancer. Your doctors may be able to tell you how concerned they are about finding cancer before the biopsy.


Types of breast biopsy

There are several different types of biopsies. The type you have depends on a number of factors, including the size of the abnormal area, what your doctor can see on your mammogram, ultrasound or other imaging test, and your personal preferences.


Minimally invasive biopsy

In minimally invasive biopsy, a radiologist—a doctor who uses imaging technology to help diagnose disease—uses a needle to take one or more tissue samples from your breast.

This procedure is usually done in an imaging center. A minimally invasive biopsy doesn’t require surgery or general anesthesia. Local anesthesia may be used to numb the affected breast.

During a minimally invasive biopsy, you’ll lie down and the radiologist will find the abnormal area by feeling for a lump. If a lump cannot be felt, the radiologist may use imaging technique like an ultrasound, mammogram, or MRI to find the area. Many times the doctor will take multiple biopsies from the same area.

Fine-needle aspiration

The least invasive kind of needle biopsy is called a fine-needle aspiration, or FNA. It involves a narrow needle that is inserted into the area where the abnormal finding was seen. Your doctors may be very likely to recommend this option if they suspect the change in your breast is not a tumor but a liquid-filled cyst that is not cancer. FNA usually causes cysts to collapse once the liquid is removed.

Doctors also may use an FNA to study enlarged lymph nodes.

If FNA does find cancer, it may not remove enough cells do perform testing to find out more about the cancer. FNA can also miss cancer if the needle doesn’t go directly into the cancer cells.

Core needle biopsy

Core needle biopsy or CNB, often called vacuum-assisted biopsy, is similar to FNA. CNB uses a larger needle and may involve taking more or larger tissue samples from the breast or from an axillary lymph node (a lymph node in the armpit). If breast cancer is suspected, CNB is often preferred over FNA because CNB can remove more tissue, making it easier to perform needed lab tests on the tissue

CNB can be done on a lump that can be felt, with guidance from an ultrasound, mammography machine or MRI machine. When the biopsy is performed using a mammography machine, it is called a stereotactic core biopsy. With a stereotactic core biopsy, you usually lie face down with your breast hanging through a hole in a special table. A small mammography machine under the table takes images that help guide the radiologist to the area to be biopsied.

After a CNB, the doctor will often place a tiny marker, called localization marker, into your breast to mark the site where the tissue samples were taken. The marker may be a metal clip, a magnetic or radioactive seed, a metal radar-friendly reflector, or other type of marker. Placing a marker in the biopsy site helps doctors find the area later in case further biopsies or surgery is needed. Most people do not get a scar from CNB.

You can learn more about localization markers in the Localization markers placed during biopsy section below.


Surgical biopsy

Doctors often recommend a minimally invasive biopsy as a first option. Your doctor may recommend a surgical biopsy if:

  • You already had a needle biopsy but more information is needed
  • They believe a needle biopsy won’t give enough information

A surgical biopsy may be called either an incisional biopsy or excisional biopsy.

  • During an incisional biopsy, a surgeon removes part of the abnormal area to make a diagnosis.
  • In an excisional biopsy, a surgeon tries to remove the entire abnormal area. An excisional biopsy is often used when the doctor suspects there may not be cancer. If the area is benign, or not cancerous, often no more surgery is needed. If cancer is found, it is likely you will need another procedure.

Surgical biopsies are done in an operating room. Most people are put to sleep for the procedure. Sometimes this involves “twilight” anesthesia and sometimes general anesthesia. There are small differences in both, so speak with your surgeon about your options.

Because the surgeon uses a scalpel to cut into your breast to remove the abnormal tissue, you will need stitches. These procedures can cause a scar, and you may need a couple of weeks to heal.


Lymph node biopsy

If breast cancer travels beyond the breast, the axillary lymph nodes in the armpit are often the first place the cancer cells go. Here are the different kinds of lymph node procedures doctors may recommend:

  • If imaging or clinical examination suggests that cancer may be in a lymph node, doctors may recommend FNA or CNB of the lymph node.
  • If cancer is found in the breast, a procedure called sentinel lymph node biopsy is usually recommended. In this type of biopsy, a surgeon will inject a blue dye or radioactive substance (or both) to identify the node or nodes closest to the breast cancer. The surgeon then removes the node or nodes for examination.
  • If more nodes need to be removed, a surgeon may perform a more involved lymph node surgery called axillary lymph node dissection.

You can learn more about these procedures on the Lymph node surgery page.


Localization markers placed during biopsy

During FNA or CNB, your radiologist or surgeon may use a needle or other device to place a marker in your breast or lymph node. This helps doctors locate the biopsy site if additional biopsies, surgeries, or treatment monitoring are needed in the same area later. Markers can also be placed at a time separate from biopsy if needed. Placing a marker in the breast or in a lymph node is part of a process called localization.

How localization markers are used

If breast cancer is diagnosed, you and your doctors will decide what cancer-removing surgery is appropriate: mastectomy or lumpectomy. If lumpectomy is recommended, a marker placed in your breast will help your surgeon to precisely locate the cancerous area when it’s time to remove it.

Localization has two parts: Marker placement and marker detection.

First, a radiologist or surgeon places a marker in the site of cancer or suspected cancer. A marker can be placed:

  • At the time of biopsy
  • After biopsy, days or weeks before cancer-removing surgery
  • On the day of surgery

Later, doctors can use a device to locate the marker:

  • Just before cancer-removing surgery such as lumpectomy
  • After preoperative (neoadjuvant) chemotherapy to shrink the cancer, to see how well chemotherapy is working

Types of localization markers

Here are some of the different kinds of localization markers doctors may place in the breast or a lymph node:

  • Metal clips that can be detected with imaging and a needle-guided wire inserted into the breast
  • Markers that are used with wireless detection technologies, including:

    • Magnetic seeds, detected by a probe that picks up the magnetic signal
    • Radar reflectors, detected by a probe that emits radar waves
    • Radiofrequency identification markers that have a numbered tag; a radiofrequency probe can detect the tag
    • Radioactive seeds that can be found with a radiation detection probe
    • Natural mineral-based (non-metal) clips that can be found with ultrasound technology

Localization markers can also help doctors monitor the progress of any treatments you may have before surgery (neoadjuvant treatment) to shrink the cancer.  

If you have questions or concerns about the type of localization marker or detection method your hospital uses, talk with your radiologist, imaging center coordinator, or breast surgeon. It’s important to know that there are options, and you can talk with your care team about what is right for you. 

Learn more about wire and wire-free localization, including risks and benefits, on the Surgery page.

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