What Is a Breast Biopsy?

A breast biopsy is the removal of a sample of breast tissue so that it can be tested for breast cancer. This can be done in a few ways. With a core needle biopsy, ultrasound or MRI guidance may be used. With an open procedure, stereotactic surgery or wire localization may be recommended to make sure the biopsy samples the abnormality. Overall, 70% to 80% of biopsies will be negative for cancer, but they may reveal benign breast diseases or conditions that predispose you to breast cancer.

A breast biopsy may be recommended if a person develops symptoms of breast cancer or if an abnormality is found on a screening test or follow-up tests, such as a mammogram, breast ultrasound, or breast MRI.

Symptoms of breast cancer that may call for a biopsy include:

• A breast lump
• Breast dimpling
• An orange peel appearance to the breast
• Skin thickening on the breast
• Nipple changes, such as a retracted nipple
• Nipple discharge
• A red rash or sores on the breast
• Enlarging veins on the breast
• A change in size, shape, or weight of a breast
• An enlarged lymph node in the armpit

Findings on imaging tests that may suggest the need for a biopsy include, but are not limited to:

• The presence of microcalcifications or a spindle-shaped mass on mammogram
• A solid or partly solid lump on breast ultrasound
• A mass with irregular borders on a breast MRI

A biopsy can be used to detect breast cancer in women as well as men.

Women who have a high risk of developing breast cancer, such as those who have a strong family history or gene mutations linked with breast cancer, are now often screened with a combination of MRI and mammogram. According to a 2018 study published In JAMA Internal Medicine, more biopsies are performed due to MRI screenings than mammogram screenings, but these biopsies are less likely to be positive for breast cancer.

Much less commonly, a breast biopsy may be done when a person is first diagnosed with breast cancer because of metastases to another region of the body (such as the bones, liver, lungs, or brain).

A breast biopsy may be done in one of several ways:

• Fine needle aspiration: This involves inserting a thin needle through the skin in order to collect a sample of cells. It is particularly helpful in distinguishing fluid-filled cysts from solid masses.
• Core needle biopsy: This requires the use of a larger needle than a fine needle biopsy and removes a core of tissue, rather than a collection of cells. It is often done using ultrasound or MRI for guidance.
• Open (surgical) biopsy: An open biopsy may be incisional (involving the removal of part of the abnormality) or excisional (removing all of the abnormality).

If the abnormality can be seen with imaging but not felt, ultrasound guidance, MRI guidance, stereotactic methods (stereotactic breast biopsy), or wire localization may be needed to make sure the biopsy takes a sample from the abnormal region.

A skin biopsy or nipple biopsy may also be done if inflammatory breast cancer or Paget's disease of the nipple is suspected.

These procedures are different in a number of ways, and your doctor can help determine which one is most appropriate for you.

With a fine needle biopsy, if the cells are malignant (cancerous), it is not usually possible to determine the tumor grade (aggressiveness); whether the cancer is in situ or invasive; or whether receptors (such as estrogen receptors) are positive or negative.

If the results of a fine needle aspiration or core needle biopsy are unclear, or if cancer can't be ruled out even if the results are negative, an open biopsy is usually recommended, as it can provide additional information. However, surgical biopsies can lead to scarring or disfigurement of the breast, depending on the amount of tissue removed.

All types of breast biopsy carry the risk of false positives and false negatives.

False negatives occur when a cancer is present but the biopsy fails to detect it. It is more common with fine needle aspiration and least common with an open surgical biopsy, but overall, the risk is relatively low. False negatives are more common when a breast mass cannot be felt on exam.

False positive results occur when a biopsy suggests cancer is present when it is actually not. In a 2015 study published in JAMA, false positive findings were noted on 17% of breast biopsies. False positive diagnoses were less likely to occur with invasive cancer and more commonly seen with ductal carcinoma in situ (DCIS) and atypical hyperplasia.

As with any medical procedure, biopsies carry potential risks and reasons why the procedure should not be done.

Bleeding and infection are potential risks of any type of breast biopsy, as a passageway is created from the skin to the breast to collect cells or tissue.

There is also a very small risk of the needle used for a fine needle or core biopsy penetrating the lungs and causing a pneumothorax (collapse of a lung). This is more common when the biopsy site is very deep in the breast.

Further, core needle biopsy has a small risk that the procedure will "seed" (spill) tumor cells along the track of the needle, increasing the risk of metastases. While a 2009 review of 15 studies did not find any difference in survival in women who had this procedure as opposed to another form of breast biopsy, a 2017 study found that a core needle biopsy was associated with a higher rate of distant metastases five to 15 years after diagnosis, relative to people who had a fine needle aspiration biopsy.

The risks associated with local and general anesthesia, as applicable, are also possibilities.

The use of blood thinners is a relative contraindication to a biopsy, meaning that it's important to weigh the benefits of the test vs. the risks of bleeding. Often, it's recommended that these medications, as well as aspirin and anti-inflammatory medications like Advil (ibuprofen), be stopped for a few days before the procedure.

Other considerations that may rule out a breast biopsy in some people include:

• In women who are breastfeeding, some procedures may be more likely to result in a milk fistula.
• In women with silicone breast implants, a core needle biopsy may not be advisable.
• Using vacuum assistance with a core needle biopsy may be ineffective if the lesion is near the chest wall.
• The tables used for stereotactic biopsies often have a weight limit of 300 pounds.
• Stereotactic localization involves radiation, and benefits and risks need to be weighed carefully in pregnant women.

When your doctor recommends a breast biopsy, she will discuss the reasons why she thinks it is indicated for you and any potential risks. She will ask you about any previous procedures you have had done on your breast, as well as any health conditions you manage. In particular, she will review your risk factors for breast cancer, including your menstrual history, the number of pregnancies you've had, and any family history of breast cancer or other cancers.

The amount of time required for a breast biopsy depends on the particular type you will be having. A needle biopsy when a lump can be palpated (felt by your doctor) may take only five to 10 minutes. A core biopsy often takes 15 to 30 minutes but may require more time if ultrasound or MRI guidance is needed.

With an open biopsy, you will want to set aside several hours to allow for the test, as well as preparation and recovery time. If wire localization or a stereotactic procedure is done, this can take up to an hour or more of additional time prior to surgery.

A needle biopsy or core biopsy may be done in a clinic, although these procedures are usually done in a radiology department if ultrasound guidance is needed. For an open surgical biopsy, the procedure is usually done in an outpatient surgery center or as an outpatient procedure at a hospital.

You will be asked to remove your clothing and change into a gown before your biopsy procedure (usually just from the waist up for a needle or core biopsy). Afterward, plan to wear a supportive, but not tight, bra—doing so, possibly for as much as 24 hours, may be advised.

Usually, for a needle or core biopsy, there are no restrictions in this regard. With a surgical biopsy, you will likely be asked to avoid eating or drinking anything for several hours or after midnight on the day before the procedure.

You should talk to your doctor about any medications you take prior to the procedure. If you are taking any blood thinners, these may need to be stopped for several days, but this should only be done after discussing the risks with the physician who prescribes these drugs.

Keep in mind that some over-the-counter medications (such as ibuprofen and aspirin), as well as some vitamins and dietary supplements, may also thin the blood. These preparations may need to be stopped a week or longer before your biopsy.

If you smoke, quitting before your biopsy reduces the risk of infection and improves wound healing. Refraining from smoking for even a day or two prior to your procedure may have benefits. (Quitting smoking is important not only for your biopsy. A few large studies including the 2017 Generations Study now suggest that smoking is a significant risk factor for breast cancer.)

Most private insurers, as well as Medicare, cover the cost of a breast biopsy when indicated. With some insurance companies, or when special techniques are recommended, you may need to obtain prior authorization.

You should bring your insurance card with you on the day of your procedure, and you may be asked to bring any imaging tests or prior biopsy reports with you. Most often, you will be asked to bring the actual films or a CD of imaging tests such as mammograms, rather than the written report.

It's always a good idea to bring a book, magazine, or another item to entertain yourself should your appointment be delayed.

If you'll be having a surgical biopsy, you'll need to bring a companion with you who can drive you home. Even if the biopsy is done under local or regional anesthesia, rather than general, the medications you receive to relax you can interfere with driving.

With a needle or core biopsy, you will usually be attended to by a nurse or technician as well as a doctor. During an open biopsy, a nurse (and often your doctor and anesthesiologist) will talk to you before the procedure. In the operating room, there will be a few nurses including a scrub nurse, your surgeon, your surgeon's assistant (if she has one), a nurse anesthetist who will stay with you, and an anesthesiologist who will monitor your progress.

After changing out of your clothes, your doctor will ask if you have any questions. You will also be asked to sign an informed consent form indicating that you understand the purpose of the procedure and any potential risks.

If you will be having an open biopsy, your nurse will place an IV and attach monitors that will record your heartbeat and the oxygen level in your blood. If you will be having a general anesthetic, the anesthesiologist will talk to you and ask about any problems you or anyone in your family have had with anesthesia in the past.

The breast biopsy procedure itself will vary depending on the type of biopsy you are having.

Regardless, when a stereotactic breast biopsy procedure is used, a person usually lays on their stomach with their breast hanging through a special hole in the table. Digital mammogram images are taken from different angles to create a 3-dimensional view of the breast. When the precise location is defined, a needle biopsy may then be done, or the area is marked with a wire for an open biopsy.

Fine Needle Biopsy (FNA)

With fine needle aspiration, your skin will be cleansed with a disinfectant and a long narrow needle placed into the lump or abnormal area. A syringe is then attached to provide suction. If fluid is present, such as with a cyst, it will be withdrawn; with a simple cyst, the lump may disappear completely as a result. If the lump is solid, a collection of cells will be collected. Once the sample is obtained, the syringe is removed and the area dressed.

Core Needle Biopsy

With a core needle biopsy, the skin is disinfected and then anesthetized locally with lidocaine. A small cut is then made in the skin and a needle (larger than is used for FNA) is inserted through the skin and into the mass. This is often done with ultrasound (or MRI) guidance, even if a lump can be palpated. You may feel some pressure or a tugging feeling while the needle enters your breast.

When the doctor is certain the needle is in the correct area, a spring-loaded instrument is used to obtain a grain-sized sample of tissue. Often, four to eight core samples are taken. When that is done, a clip is often placed in the region of the biopsy so that it can be identified as such during a future mammogram or surgery. (This clip will not be a problem if an MRI is needed.) Once the clip is placed, the needle is removed and pressure is placed on the wound for several seconds before a dressing is applied.

A vacuum-assisted core biopsy is an alternative procedure in which a vacuum is attached to the hollow needle; it usually obtains a larger sample of tissue than a typical core biopsy.

Surgical (Open) Biopsy

In the operating suite, you will be asked to lie on your back, and a curtain may be placed between your head and the surgical field. The procedure may be done with either a general anesthetic or with sedation followed by a local anesthetic.

Your breast will be cleansed with a disinfectant and surgical drapes placed to keep the field sterile. If you will be awake, a local anesthetic will be injected first into the skin over the area of concern, and then deeper in your breast. You will feel a pinch when the needle penetrates your skin and may feel an ache in your breast as the surgeon injects more lidocaine. With a general anesthetic, you will be asleep throughout the procedure.

After you're asleep or when your breast is numb, the surgeon will make an incision over the area of concern in your breast. If you're awake, you may feel pressure and a tugging-sensation as she removes a section of tissue. This may either be a portion of the mass (an incisional biopsy) or the entire mass and a margin of tissue surrounding the mass (excisional biopsy).

When the procedure is done, the incision will be closed with sutures and dressings applied.

The sample(s) collected are sent to a pathologist for review after your test is complete.

With a needle or core biopsy, pressure will be placed over the site where the needle entered. You will be watched for a short while and be able to return home as soon as you are feeling comfortable.

With a surgical biopsy, you'll be observed in the recovery room until you're awake. You may be given crackers and juice. When you're fully awake and comfortable, your monitors will be removed and you may return home.

With a needle or core biopsy, you will be asked to keep the area where the needle entered clean and dry, and you may be advised to remove the dressing in a day or two. Some bruising and aching is normal, and your doctor may recommend that you sleep in your bra to keep pressure on the site for a few days. It's best to avoid strenuous activity for the first several days.

With an open biopsy, you may be asked to leave your surgical dressings in place until you follow up with your doctor. Some physicians advise wearing a bra around the clock to provide compression and reduce bruising.

During this time, you should avoid bathing or showering, but you may give yourself a sponge bath and wash your hair in the sink or tub. The arm on the side of your biopsy may be sore, and you may want help.

The fewest post-procedure symptoms are often noted with a fine needle aspiration and the most with an open biopsy.

Swelling and discomfort may occur for a few days depending on the site and size of the biopsy. Ice packs may help, and some clinics may provide ones that can be placed in your bra. You may be advised to use Tylenol (acetaminophen) or Advil (ibuprofen) to ease any pain.

Your doctor may call you on the phone or ask that you return to the clinic to discuss your results. Even if you receive a preliminary report at the time of the biopsy, the final pathology report and further tests, if needed, often take at least a few days to complete.

Biopsy results are negative, positive, or inconclusive; in the case of the latter, another biopsy or other studies may be needed.

Findings may be listed on the report as:

• Normal
• Benign (noncancerous) breast conditions
• Benign breast conditions that increase the risk of cancer
• Carcinoma in situ
• Cancer

A negative result means that there is no evidence of cancer or benign breast conditions present.

Many different benign breast conditions can be found on a biopsy, many of which are not associated with an increased risk of breast cancer. Some of these include:

• Fibroadenomas
• Benign breast cysts
• Fat necrosis
• Oil cysts

Some benign breast conditions are associated with an increased risk of developing breast cancer in the future. Some of these conditions include:

• Atypical hyperplasia: Atypical hyperplasia is considered a precancerous condition. For example, roughly 40% of people with lobular hyperplasia will develop invasive cancer within 15 years of diagnosis.
• Radial scar: Having a radial scar roughly doubles the risk of developing breast cancer.
• Adenosis: Breast adenosis is a benign condition, but those who have adenosis are about .7 times more likely to develop breast cancer.

Carcinoma in situ refers to a group of abnormal cells that appear identical to breast cancer, but have not extended beyond the basement membrane. Since they have not extended past this region, they are considered noninvasive, and removal of the cluster of abnormal cells should—in theory—provide a cure. The two types of carcinoma in situ are:

• Ductal carcinoma in situ (DCIS)
• Lobular carcinoma in situ (LCIS)

Note, though, that areas of carcinoma in situ can also exist along with invasive cancer.

Overall, between 20% and 30% of breast biopsies are positive for cancer. If your biopsy reveals cancer, your report will describe the tumor in a number of ways (with the exception of a fine needle biopsy).

The type of breast cancer will be listed and may include:

• Ductal carcinoma: Cancers that arise in the milk ducts, ductal carcinomas are the most common type of breast cancer.
• Lobular carcinoma: This arises in the lobules of the breast and is the second most common form of breast cancer.
• Inflammatory breast cancer
• Uncommon forms of breast cancer, such as medullary carcinoma, tubular carcinoma, mucinous carcinoma, and others

The tumor grade will be a number between 1 and 3, with 1 being used for the least aggressive cancers and 3 being used for the most aggressive.

Special tests that are done to determine the hormone receptor status (whether the tumor is estrogen and/or progesterone receptor positive) and HER2 status (whether the cancer is HER2 positive) will be listed as either positive or negative.

If you have a surgical (open) biopsy, your pathology report will also comment about the tumor margins—the edges of the sample that was removed. Whether all of the tumor was found within the sample or if any tumor is near or extending beyond the edge of the biopsy specimen will be noted.

• With negative margins, all of the tumor cells are found well within the surgery specimen (the tumor was completely removed).
• With close surgical margins, the tumor is found completely within the biopsy sample, but extends to within 3 millimeters of the edge.
• With positive margins, there is evidence that tumor exists all the way to the edge of the biopsy sample, and it's likely that some of the tumor was left behind in the breast.

A biopsy cannot determine if breast cancer has spread to lymph nodes or distant regions of the body, and therefore cannot tell you the stage of cancer.

The follow-up after your breast biopsy will vary depending on the results. Whether your biopsy is positive or negative, you may wish to talk to your doctor about genetic testing if you have a strong family history of breast cancer.

If your biopsy is negative, your doctor will talk to you about the next steps. If the likelihood of cancer is low and the result is negative, she may simply recommend that you follow-up with routine breast screenings. Since guidelines for screening have been changing, and since these are designed for people who have an average risk of breast cancer, it's important to talk to your doctor about the best next steps for you specifically.

Since biopsies can sometimes miss a tumor, your doctor may recommend a repeat biopsy or other testing if she still believes there is a chance that your lump or imaging finding could be cancer.

If you have a benign breast condition, follow-up is usually similar to those who have negative results. With benign conditions that increase breast cancer risk, the next steps will depend on your expected risk. For those who have atypical hyperplasia, medications such as Tamoxifen or prophylactic breast surgery may be recommended. For those who do not have surgery, careful follow-up, often with screening MRIs, may be recommended.

Carcinoma in situ is often treated with surgery similar to breast cancer, though adjuvant treatment, such as chemotherapy, is not usually needed.

If your biopsy indicates cancer, the first decision is usually to choose between a lumpectomy and mastectomy (unless you had a wide excisional biopsy with clear margins). There is usually plenty of time before surgery needs to be done, and many people wish to consider a second opinion before making this decision. Further treatments will depend on the stage of cancer and may include chemotherapy, radiation therapy, hormonal therapy, and/or HER2-targeted therapy.

Breast cancer is far too common, and most people know of someone who has had to cope with the disease. It's important to understand that a breast biopsy is more likely to reveal benign changes than cancer. Even if cancer is found, the majority of them will be early-stage tumors. The treatment of these cases has improved, with newer options significantly reducing the risk of recurrence and often being far less invasive than older ones. Even with metastatic breast cancer, treatments are improving and life expectancy is increasing.