Core needle biopsy uses a hollow needle to remove samples of tissue from the breast. It can be used to biopsy a:
- Lump that can be felt (palpable mass)
- Suspicious area that can only be seen on a mammogram or other imaging test (nonpalpable mass)
Core needle biopsy is often the preferred biopsy method because it is accurate and does not involve surgery.
Core needle biopsy for palpable masses
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.
Core needle biopsy for nonpalpable masses
For a nonpalpable mass, a core needle biopsy is slightly more involved. It will likely be done in a 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 using either types of imaging .
Core needle biopsy with stereotactic mammography
During a needle biopsy with stereotactic mammography, you lie on your stomach on a special table and your breast fits through a hole in the table (see Figure 4.2).
Before the procedure, the health care provider will use a local anesthetic to numb the area. Your breast will be compressed like it is for a mammogram, and several images will be taken. These images help the provider guide the biopsy device to the suspicious area in the breast. A needle in the device removes tissue samples. In some centers, the needle removes tissue with a vacuum assisted probe. The needle is inserted and removed quickly. You may feel a pushing and pulling sensation on your breast, which can cause some discomfort.
Core needle biopsy with ultrasound
During a core needle biopsy with ultrasound, you lie on your back. Before the biopsy procedure, the provider will use a local anesthetic to numb the area.
The health care provider holds the ultrasound device against your breast to see the area. The ultrasound image helps the provider guide the needle as it enters the breast and reaches the abnormal area. The provider then removes a sample of tissue with the needle. In some centers, this is done with a vacuum assisted device. The needle is inserted and removed quickly. You may feel a pushing and pulling sensation on your breast, which can cause some discomfort.
Advantages of core needle biopsy
Core needle biopsy is accurate when done by an experienced radiologist. It is quick and does not involve surgery. There is only a small chance of infection or bruising.
If breast cancer is found, the tissue removed during a core needle biopsy gives important information including:
This information helps you and your health care provider plan your treatment.
If the tissue sample is benign (not cancerous), surgery may be avoided. In some cases, however, even if the tissue sample is benign, an excisional biopsy (a surgical biopsy) may be needed to confirm the diagnosis.
Drawbacks 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.
If a tumor is missed, the biopsy will show cancer does not exist when in fact, it does. This is called a false negative result and can delay diagnosis. For nonpalpable masses, false negative results occur in up to eight percent of stereotactic mammography- or ultrasound-guided core needle biopsies . For palpable masses, false negative results are more rare .
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, it can't tell whether a tumor is ductal carcinoma in situ or invasive breast 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.