Core needle biopsy uses a thin, hollow needle to remove tissue from the breast. It can be used on suspicious areas that can be felt (palpable masses) and those that can only be seen on a mammogram or other imaging test (nonpalpable masses). Because it is accurate and does not involve surgery, it is often the preferred biopsy method.
If a lump can be felt, a core needle biopsy can be done in a health care provider's office. Before the procedure begins, the provider will use a small amount of local anesthetic to numb the skin and breast tissue around the suspicious area. He/she will then insert the needle and remove a small amount of tissue.
For a nonpalpable mass, a needle biopsy is slightly more involved. It will likely be done in an outpatient clinic or imaging center. The health care provider will locate the abnormal area with the help of ultrasound or a special type of three-dimensional mammography, called stereotactic mammography. The accuracy is similar for both types of images [3].
During a needle biopsy with stereotactic mammography, you lie on your stomach on a mammography table with your breast fitting through a hole in the table. Your breast is compressed like it is for a mammogram, and several images are taken. Based on the images, a biopsy device containing a needle takes tissue samples from the abnormal area. Before the procedure, the health care provider uses a local anesthetic to numb the area. The needle is inserted and removed quickly. You will feel a pushing and pulling sensation on your breast, which causes some discomfort. Figure 4.2 illustrates the procedure.
During a needle biopsy with ultrasound, you lie on your back while the health care provider holds the ultrasound device against your breast to see the area. The provider will use a local anesthetic to numb the area and insert the needle and remove a sample of tissue. The ultrasound image helps the provider guide the needle as it enters the breast and reaches the abnormal area. You will feel a pushing and pulling sensation on your breast, which causes some discomfort.
Advantages of core needle biopsy
Core needle biopsy is accurate when done by an experienced radiologist. It is also quick, fairly inexpensive and does not involve surgery. In rare cases, it leads to problems like infection or bruising. Core needle biopsies give important information about the suspicious area, such as the tumor type, tumor grade and hormone receptor status if cancer is found. Such information helps you and your health care provider plan your treatment. And, if the area turns out to be benign (not cancerous), more invasive surgery may be avoided. In some cases, however, even if a tumor is benign, your health care provider may feel that an excisional biopsy is needed.
Disadvantages of core needle biopsy
One drawback of core needle biopsy is that the needle can miss a tumor and take a sample of normal tissue instead. This is most likely to occur when the biopsy is done without the help of stereotactic mammography or ultrasound guidance. If a tumor is missed, the biopsy will show that cancer does not exist when in fact, it does. This is called a false negative result and can delay diagnosis. False negative results occur in up to eight percent of stereotactic or ultrasound-guided core needle biopsies of nonpalpable masses [3]. False negative results for palpable masses are more rare [4].
Another drawback of core needle biopsy is that it may not give full information about the tumor. For example, it can't tell the size of a tumor and sometimes can't tell if a tumor is ductal carcinoma in situ or invasive cancer. Taking multiple tissue samples can help limit this problem. However, in some cases, a surgical biopsy is needed to get complete information on the tumor.
Updated 10/26/09
