Biopsy

During a biopsy the doctor removes a sample of the abnormal area to be looked at under a microscope. A biopsy may be done when mammograms, other imaging tests, or the physical exam finds a breast change that may be cancer. A biopsy is the only way to tell if cancer is really present.

There are several types of biopsy procedures, and each type has its own pros and cons. The choice of which to use depends on your situation. Some of the factors your doctor will take into account include:

• How suspicious the lesion looks
• How large it is
• Where it is in the breast
• How many lesions there are
• Other medical problems you may have
• Your personal preferences

If you need a biopsy, you might want to talk about the different biopsy types with your doctor.

Fine needle aspiration (FNA) biopsy

In FNA biopsy, the doctor uses a very thin, hollow needle attached to a syringe to withdraw (aspirate) a small amount of fluid or tissue from a suspicious area. The biopsy sample is then looked at under a microscope. The needle used for FNA is thinner than the ones used for blood tests.

If the area to be biopsied can be felt, the needle can be guided into that area of the breast as the doctor is feeling it.

If the lump can't be felt easily, the doctor might use ultrasound to watch the needle on a screen as it moves toward and into the mass.

A local anesthetic (numbing medicine) might or might not be used. Because such a thin needle is used for the biopsy, the shot to numb the breast may hurt more than the biopsy itself.

Once the needle is in place, either fluid or tissue from the mass is drawn out. Clear fluid means that 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 doctor will look at the biopsy tissue or fluid under a microscope to see if it contains cancer cells.

An FNA biopsy is easier to have done than other types of biopsy procedures, but it can sometimes miss a cancer if the needle is not put into the right spot. And even if cancer cells are found, it is usually not possible to know if the cancer is invasive (the kind that can spread). In some cases of cancer, there may not be enough cells to do some of the other routine lab tests. If the FNA biopsy does not provide a clear diagnosis or if more information is needed, a second FNA or a different type of biopsy may need to be done.

Core needle biopsy

A core needle biopsy is much like an FNA biopsy, but it uses a slightly larger, hollow needle to withdraw small cylinders (or cores) of tissue from the abnormal area in the breast. The procedure is most often done with local anesthesia (you are awake but your breast is numbed) in the doctor's office or clinic.

The needle is put into the abnormal area several times to get the samples, or cores, which are about 1/16 inch to 1/8 inch in width and about half an inch long. If the doctor is biopsying a lump that can be felt, he or she can guide the needle into the abnormal area while feeling the lump. If the abnormal area is too small to be felt, the doctor may use ultrasound or mammograms to guide the needle to the target area. (When mammograms taken from different angles are used to pinpoint the biopsy site, this is known as a stereotactic core needle biopsy.) In some centers, the biopsy can be guided by an MRI scan.

The core needle biopsy is slightly more complex and takes longer than an FNA biopsy, but it is also more likely to give a definite result because more tissue is taken to be studied. This type of biopsy can cause some bruising, but it usually does not leave scars.

Vacuum-assisted biopsies: Vacuum-assisted biopsies can be done with systems such as the Mammotome^® or ATEC^® (Automated Tissue Excision and Collection). For these procedures the breast skin is numbed and a small cut (about ¼ inch) is made. A hollow probe is put into the cut and into the abnormal area of breast tissue. The probe can be guided into place using x-rays or ultrasound (or MRI in the case of the ATEC system). A cylinder of tissue is then sucked in through a hole in the side of the probe, and a rotating knife within the probe cuts the tissue sample from the rest of the breast. Many samples can be taken from the same cut in the skin. Vacuum-assisted biopsies are done as an outpatient procedure. No stitches are needed, and there is little scarring. This method usually removes more tissue than core needle biopsies.

Surgical (open) biopsy

Doctors usually prefer to do needle biopsies to determine if a suspicious area is breast cancer, but in rare cases surgery is needed to take out all or part of the lump for a biopsy. This is called a surgical biopsy or an open biopsy. Usually this is an excisional biopsy, where the surgeon removes the entire mass or abnormal area, often with some of the normal tissue around it. If the mass is too large to be removed easily, an incisional biopsy may be done, where only part of the mass is removed (although a core needle of FNA biopsy is more likely to be done instead).

In rare cases, this type of biopsy can be done in the doctor's office, but it is more often done in the hospital outpatient department. Depending on the extent of the biopsy, you may be given a local anesthetic to numb your breast and possibly a sedative to make you drowsy. Or the biopsy can be done under general anesthesia, where you are asleep.

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, the surgeon may use a procedure called stereotactic wire localization. First the area is numbed with a local anesthetic. Then a thin, hollow needle is put into the breast and x-ray views are used to guide the needle to the suspicious area. Once the needle tip is in the right spot, a thin wire is put 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 surgeon uses the wire to find the abnormal tissue that is to be removed.

The surgical specimen is sent to the lab to be looked at under a microscope. Further treatment is based on what is found.

This type of biopsy is more involved than an FNA biopsy or a core needle biopsy. It often requires several stitches, and may leave a scar. The more tissue removed, the more likely it is that you will notice a change in the shape of your breast afterward. A core needle biopsy usually gets enough tissue to be sure what the abnormal area is. But sometimes an open biopsy may be needed depending on where the abnormality is, or if the core biopsy doesn't get enough tissue to be sure.

Biopsy accuracy

FNA, core needle, and surgical biopsies are all very good at finding cancer. Less data is available on the newer vacuum-assisted core biopsy techniques. The accuracy of each method depends to a great degree on the doctor's experience with that method. This is especially true with methods that remove smaller amounts of tissue, like the FNA and core needle biopsy. A very precise needle placement is needed so that these methods can give accurate results.