Each type of biopsy has pros and cons. The choice of which type to use depends on your situation. Some of the things your doctor will consider include how suspicious the tumor looks, how big it is, where it is in the breast, how many tumors there are, other medical problems you might have, and your personal preferences. You might want to talk to your doctor about the pros and cons of different biopsy types.
Fine needle aspiration biopsy
In fine needle aspiration biopsy (FNAB), the doctor (a pathologist, radiologist, or surgeon) uses a very thin needle attached to a syringe to withdraw (aspirate) a small amount of tissue from the suspicious area. This tissue is then looked at under a microscope. The needle used for FNAB is thinner than the ones used for blood tests.
If the area to be biopsied can be felt, the doctor locates the lump or suspicious area and guides the needle there. If the lump can’t be felt, the doctor might use ultrasound to watch the needle on a screen as it moves toward and into the mass. (This is called an ultrasound-guided biopsy.) Or, the doctor may use a method called stereotactic needle biopsy to guide the needle. For a stereotactic needle biopsy, computers map the exact location of the mass using mammograms taken from 2 angles. This helps the doctor guide the needle to the right spot.
The doctor may or may not use a numbing medicine (called a local anesthetic). The needle used for the biopsy is so thin that getting the medicine may hurt more than the biopsy itself.
Once the needle is in place, fluid or tissue is drawn out. If clear fluid is withdrawn, the lump is more likely a benign cyst (not cancer). Bloody or cloudy fluid can mean either a benign cyst or, less often, cancer. If the lump is solid, small pieces of tissue are drawn out. A pathologist (a doctor who is expert in diagnosing disease from tissue samples) will look at the biopsy tissue or fluid under a microscope to find out if it’s cancer.
A fine needle aspiration biopsy can sometimes miss cancer if the needle does not get a tissue sample from the area of cancer cells. If it does not give a clear diagnosis, or your doctor still has concerns, a second biopsy or a different type of biopsy should be done.
If you are still having menstrual periods (that is, if you are pre-menopausal), you most likely know that breast lumpiness can come and go each month with your menstrual cycle. If you have a breast lump that needs to be checked, the doctor will start by taking your history and doing a physical exam, and then setting up breast imaging. If you have a lump that doesn’t go away, or the collected information doesn’t clearly tell what the problem is, the doctor may want to do a fine needle aspiration biopsy to see if it’s a cyst (a fluid-filled sac) or a solid growth (mass or tumor). If an aspiration is done and the lump goes away after it’s drained, it usually means it was a cyst and not cancer. Again, most breast lumps are not cancer.
Talk to your doctor about what type of biopsy is best for you and what you can expect it to be like.
Core needle biopsy
A core needle biopsy (CNB) is much like an FNAB. A slightly larger, hollow needle is used to withdraw small cylinders (or cores) of tissue from the abnormal area in the breast. CNB is most often done in the doctor’s office with local anesthesia (you are awake but your breast is numbed). The needle is put in 3 to 6 times to get the samples, or cores. This takes longer than an FNAB, but it’s more likely to give a clear result because more tissue is taken to be checked. CNB can cause some bruising, but usually does not leave scars inside or outside the breast.
The doctor doing the CNB usually places the needle in the abnormal area using image guidance (ultrasound or x-rays) to be sure it’s in the right place. If the area is easily felt on physical exam, the biopsy needle may be guided into the mass while feeling (palpating) the lump.
Stereotactic core needle biopsy
A stereotactic core needle biopsy uses x-ray equipment and a computer to analyze the pictures (x-ray views). The computer then pinpoints exactly where in the abnormal area the needle tip needs to go. This is often done to biopsy suspicious microcalcifications (tiny calcium deposits) when no mass can be felt or seen on ultrasound.
Vacuum-assisted core biopsy
Vacuum-assisted biopsies can be done with systems like the Mammotome® or ATEC® (Automated Tissue Excision and Collection). For these procedures the skin is numbed and a small cut (less than ¼ inch) is made. A hollow probe is put in through the cut and guided into the abnormal area of breast tissue using x-rays, ultrasound, or MRI. A cylinder of tissue is then pulled into the probe through a hole in its side, and a rotating knife inside the probe cuts the tissue sample from the rest of the breast.
These methods allow multiple tissue samples to be removed through one small opening. They are also able to remove more tissue than a standard core biopsy. Vacuum-assisted core biopsies are done in outpatient settings. No stitches are needed, and there is usually very little scarring.
Magnetic resonance imaging (MRI) guided biopsy: Sometimes the biopsy is guided by an MRI, for instance, with the ATEC system discussed above. You lay face down on a special table with an opening that your breast fits into. Computers are then used to find the tumor, plot its location, and help aim the probe into the tumor. This is helpful for women with a suspicious area that can only be found by MRI.
Surgical (open) biopsy
Most doctors will first try to figure out the cause of a breast change by doing a needle biopsy, but in some cases a surgical biopsy may be recommended. A surgical biopsy is done by cutting the breast to take out all or part of the lump so it can be looked at under the microscope. This may also be called an open biopsy. There are 2 types: incisional biopsies and excisional biopsies.
- An incisional biopsy removes only part of the suspicious area, enough to make a diagnosis.
- An excisional biopsy removes the entire mass or abnormal area, with or without trying to take out an edge of normal breast tissue (it depends on the reason for the excisional biopsy).
In rare cases, a surgical biopsy can be done in the doctor’s office, but it’s more often done in the hospital’s outpatient department under local anesthesia (you are awake, but your breast is numb). You may also be given medicine to make you sleepy. This type of biopsy can also be done under general anesthesia (you are given drugs to put you into a deep sleep so that you don’t feel any pain).
The surgeon may use a procedure called wire localization to do an open biopsy if there is a small lump that is hard to find by touch, or if an area looks suspicious on the mammogram but cannot be felt. For wire localization, the breast is numbed with local anesthetic and a thin, hollow needle is put into the breast while x-rays are used to guide it to the suspicious area. A very thin wire is put in through the center of the needle. A small hook at the end of the wire keeps it in place. The hollow needle is then removed, and the wire is left to guide the surgeon to the abnormal area.
A surgical biopsy is more involved than a fine needle aspiration or a core needle biopsy. Stitches are often needed and it will leave a scar. The more tissue removed, the more likely it is that you will notice a change in the shape of your breast. Your doctor will tell you how to care for the biopsy site and what you can and can’t do while it heals.
All biopsies can cause bleeding and swelling. This can make it seem like the breast lump is bigger after the biopsy. This is usually nothing to worry about and the bleeding and bruising go away quickly in most cases.
After the doctor has taken out all of the tissue samples needed, a very small, safe marker or clip may be put in your breast at the biopsy site. These clips are tiny, surgical-grade, metal devices that show up on mammograms and are used to mark the biopsy site. The clip cannot be felt and should not cause any problems. It’s used to mark the area in case changes show up on future mammograms.