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 large it is, where it is in the breast, how many tumors are present, other medical problems you may 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. 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). Because such a thin needle is used for the biopsy, getting the medicine may hurt more than the biopsy itself.
Once the needle is in place, fluid or tissue is drawn out. If the fluid is clear, the lump is most likely a benign cyst. Bloody or cloudy fluid can mean either a benign cyst or, very rarely, a 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 is cancer.
A fine needle aspiration biopsy can sometimes miss a 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 is still suspicious, a second biopsy or a different type of biopsy should be done.
If you are still having menstrual periods (that is, if you are premenopausal), you most likely know that breast lumpiness can come and go each month with your menstrual cycle. But if you have a lump that doesn't go away, the doctor may want to do a FNAB to see if it is 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 is drained, it usually means it was a cyst and not cancer. Again, most breast lumps are not cancer.
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 with local anesthesia (you are awake but your breast is numbed) in the doctor's office. The needle is put in 3 to 6 times to get the samples, or cores. This takes longer than an FNAB, but it is more likely to give a definite result because more tissue is taken to be looked at. CNB can cause some bruising, but usually does not leave scars inside or outside the breast.
The doctor doing the FNAB or CNB usually guides the needle into the abnormal area while feeling (palpating) the lump. If the abnormal area is too small to be felt, a radiologist or other doctor may use a stereotactic instrument or ultrasound to guide the needle to the target area.
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 type is often used to biopsy microcalcifications (tiny calcium deposits).
Larger core biopsies
Large core biopsies that use stereotactic methods remove even more tissue than a core biopsy.
Vacuum-assisted core biopsy
The Mammotome® is one type of vacuum-assisted core biopsy (VACB). For this procedure the skin is numbed and a small cut (about ¼ inch) is made. A hollow probe is put in through the cut and into the abnormal area of breast tissue. 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.
There are 2 other types of vacuum-assisted core biopsy systems:
- ATEC (short for Automated Tissue Excision and Collection)
- MIBB (short for Minimally Invasive Breast Biopsy)
All of these methods also allow tissue to be removed through a single small opening. And all are able to remove more tissue than a standard core biopsy. No stitches are needed, and there is very little scarring. Vacuum-assisted core biopsies are done in outpatient settings.
Rotating circular "cookie-cutter" knife
The ABBI method (short for Advanced Breast Biopsy Instrument) uses a probe with a rotating circular knife and thin wire to remove a larger cylinder of abnormal tissue. ABBI is guided by x-ray (stereotactic imaging), and can sometimes be used to remove an entire mass. A few stitches may be needed afterward.
Magnetic resonance imaging (MRI) guidance
In some centers, the biopsy is guided by an MRI, which uses computers to find the tumor, plot its location, and help aim the needle or biopsy device into the tumor. This is helpful for women with a suspicious area that can only be found by MRI. One of the vacuum-assisted core biopsy systems, the ATEC, is designed so that it can be used with an MRI.
Ultrasound-guided biopsy
Ultrasound-guided biopsy uses an instrument that sends out sound waves and a computer to make pictures of the breast lump. A doctor can use this method to guide a needle into very small tumors or cysts.
Surgical (excisional) biopsy
A surgical biopsy is used to remove all or part of the lump so it can be looked at under the microscope. An excisional biopsy removes the entire mass or abnormal area, as well as a surrounding margin of normal-looking breast tissue. In rare cases, this type of biopsy can be done in the doctor's office, but it is more often done in the hospital's outpatient department under a local anesthesia (where you are awake, but your breast is numb). You may also be given medicine to make you drowsy.
During an excisional breast biopsy, the surgeon may use a procedure called wire localization if there is a small lump that is hard to find by touch, or if an area looks suspicious on the x-ray but cannot be felt. After the area is numbed with local anesthetic, a thin, hollow needle is put into the breast and x-ray views are used to guide the needle 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.
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