Breast biopsy

This page was reviewed under our medical and editorial policy by

Daniel Liu, MD, Plastic and Reconstructive Surgeon

This page was reviewed on February 8, 2022.

If the care team needs to know more about the cells in a breast, they may recommend a biopsy.

What is a breast biopsy?

During a biopsy, a small sample of breast tissue is taken and sent to a lab. There, those cells are examined under a microscope to see if there’s any sign of disease.

A biopsy can tell the care team more about what’s going on, and it can help them figure out what the patient's next steps should be. Depending on the findings of the biopsy, they may recommend follow-up monitoring, surgery or another treatment.

Biopsies are a common outpatient procedure. In the United States alone, more than one million women have breast biopsies each year.

What percentage of breast biopsies are cancer?

About 25 percent of the breast biopsies performed in the United States result in a breast cancer diagnosis.

A woman's breasts might undergo small changes through her life, or big changes during pregnancy. But some breast changes aren’t normal and may signal a problem.

The care team may suggest several tests to find out more about a patient's breast changes, but the only definitive way to know if those changes are due to cancer is to get a biopsy.

Abnormal breast changes might include:

  • A lump or firmness in the breast or under the arm
  • Unusual nipple discharge
  • Red, swollen or scaly skin on any area of the breast, including the nipple and the area around it (areola)

If a woman notices any of these changes, or anything else out of the ordinary, she should reach out to a doctor. They might start to take a closer look at what’s causing the change by recommending a mammogram, or in some cases an ultrasound or MRI. To get more information, the care team may have to do a second mammogram. If they suspect there may be cancer or need more information, the next step may be a breast biopsy.

Types of breast biopsies

Though there are several different kinds of biopsies, it is often an outpatient procedure—meaning most patients will be back at home the same day.

Biopsies can look very different depending on what kind of breast changes the patient may have—including location and size.

Fine-needle aspiration breast biopsy

A fine-needle aspiration biopsy is a quick procedure that doesn’t require an incision. A very thin and hollow needle is used to take a small amount of tissue and fluid from an area of the patient's breast.

Core needle biopsy of the breast

A larger needle is used in a core needle biopsy. Small pieces of breast tissues, also called “cores,” are removed during this procedure. The care team uses an ultrasound, MRI or mammogram during the biopsy so they can guide the needle precisely where it needs to go. Depending on the imaging procedure used, the patient may be sitting up or lying on her back or stomach.

There are two types of special core biopsies:

A stereotactic core needle biopsy uses the X-rays from a mammography machine to find the abnormal area. The machine will take images from different angles and analyze the results, providing a level of detail that is especially useful for very small abnormal areas.

A vacuum-assisted core biopsy takes a sample—or several samples—while the care team uses images to guide the probe. The probe removes a tissue sample using both vacuum suction and a small knife to cut the tissue. Typically, more tissue is removed compared to a standard core needle biopsy.

No matter the type of core needle biopsy, several samples of tissue will likely be taken. A tiny marker, called a clip, may be left in the biopsy area so that the care team can monitor moving forward.

Breast surgical biopsy

If it’s not clear exactly where the abnormal cells are, the patient may need to go through one step before the biopsy itself—a “wire localization” or “needle localization”—where a marker is left to let the provider doing the biopsy know exactly where to take tissue from. In this procedure, the care team inserts a small wire while looking at mammogram pictures of the breast to be sure they place the wire precisely in the abnormal area. They’ll leave the wire there for the biopsy, and it will be removed during the biopsy itself. Sometimes newer methods such as radioactive or magnetic markers are placed in the area of concern ahead of time, rather than a wire procedure.

Just like it sounds, a surgical biopsy is more like a surgery—it removes a part or all of a lump. A small cut is made on the skin of the breast, and the surgeon will remove tissue.

There are two types of surgical biopsies, outlined below.

Breast incisional biopsy

During this procedure, the care team removes only a part of an abnormal area.

Breast excisional biopsy

In this procedure, the care team removes all of the abnormal area or lump, and some nearby tissue too.

Lymph node biopsy

The patient may have another type of biopsy called a lymph node biopsy if the care team sees a lump under the arm or has any concerns that cancerous cells may have spread. A bit of tissue is removed with a needle to help inform treatment decisions. A sentinel lymph node biopsy is often combined with breast cancer surgery, during which one or several whole lymph nodes are removed.

How to prepare for a breast biopsy procedure

While a breast biopsy doesn’t require much preparation on the patient's part, there are some potential preparation steps that may help minimize the risk of side effects.

  • Stop taking certain medications, such as aspirin or blood thinners, a few days ahead of the procedure
  • Tell the doctor about any drug allergies
  • Wear comfortable clothing to the appointment
  • Prepare to have someone else drive home—especially if sedation or general anesthesia is used
  • Allow time after the appointment to decompress

How a breast biopsy is done

When the patient arrives for her procedure, she’ll change into a hospital gown. A health professional will help her get into the right position for the procedure, depending on the type of biopsy being done, and explain what’s going to happen.

Most patients will get anesthesia ahead of the biopsy. Local anesthesia, which makes the area numb, is typically used for a needle biopsy. It also might be paired with conscious sedation or monitored anesthesia, which is IV medication to help a patient relax. For surgical biopsies, it’s more likely general anesthesia and stitches will be used.

How long does a breast biopsy take?

A breast biopsy may take as little as 20 minutes or an hour or more depending on what type of procedure is performed, how many samples are needed and if anesthesia is required.

Is a breast biopsy painful?

Local or general anesthesia is typically used during breast biopsies for the patient's comfort. Some women may experience discomfort during the procedure, but it's not typically painful.

Patients may experience some pain or tenderness for a few days after the procedure. In most cases, the pain is minimal and most patients are able to resume normal activities a day or two after a biopsy.

Breast biopsy recovery

Recovery from a breast biopsy may depend on the type of procedure performed. To prevent or reduce breast tenderness, swelling or bruising following the appointment, the care team may send the patient home with gauze and an ice pack.

Understanding breast biopsy results

After a breast biopsy, the findings will be compiled in a pathology report.

Noncancerous findings

A biopsy might reveal a type of noncancerous breast condition, which often includes lumps or bumps that can be painful at times or noncancerous abnormal cells. While these conditions aren’t cancerous, some of them may increase the risk for developing breast cancer. Next steps may include regular follow-up screenings, tests or treatment.

Cancerous findings

If the results come back as cancer, the care team will explain what was found, what it means and next steps. More testing may be recommended, as well as a referral to more experts in cancer care and treatment.

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