Core Needle Biopsy

What is Core Needle Biopsy?

A core needle biopsy is a percutaneous ("through the skin") procedure that involves removing small samples of breast tissue using a hollow "core" needle. For palpable (able to be felt) lesions, this is accomplished by fixing the lesion with one hand and performing a freehand needle biopsy with the other. In the case of non-palpable lesions (those unable to be felt), stereotactic mammography or ultrasound image guidance is used. Stereotactic mammography uses computers to pinpoint the exact location of a breast mass based on mammograms (x-rays) taken from two different angles. The computer coordinates will help the physician to guide the needle to the correct area in the breast. With ultrasound, the radiologist or surgeon will watch the needle on the ultrasound monitor to help guide it to the area of concern.

The needle used during core needle biopsy is larger than the needle used with FNA (usually a 16, 14, or 11 gauge needle is used with the core needle biopsy procedure). The core needle biopsy needle also has a special cutting edge.

How is Core Needle Biopsy Performed?

First, the breast area is anesthesized with an injection of lidocaine. Then, the needle is placed into the breast with the patient position in either the upright or prone (face down) position. As with FNA, the radiologist or surgeon will guide the needle into the area of concern by palpating (feeling) the lump. If the lump is non-palpable (cannot be felt), the core needle biopsy is performed under image-guidance using either stereotactic mammography or ultrasound.

Three to six separate core needle insertions are typically needed to obtain a sufficient sample of breast tissue. Patients may experience a slight pressure during core needle biopsy but should not experience any significant pain. As tissue samples are taken, clicks may be heard from the needle and sampling instrument. Typically, samples approximately 0.75 inches long (approximately 2.0 centimeters) and 0.0625 inches (approximately 0.16 centimeters) in diameter are removed. The samples are then sent to the pathology laboratory for diagnosis.

The core needle biopsy procedure typically only takes a few minutes, and most patients are able to resume normal activity almost immediately afterwards. Core needle biopsy may cause some bruising but does not usually leave an external scar or an internal scar that is seen on later mammograms (which can obscure future mammogram interpretations). However, core needle biopsy may not be suitable for patients who have very small or very hard breast lumps.

How Should Patients Prepare for Core Needle Biopsy?

To prepare for a core needle biopsy, patients may eat a light meal prior to the exam and biopsy procedure. A comfortable two piece garment should be worn. Women should not wear talcum powder, deodorant, lotion, or perfume under their arms or on their breasts on the day of the procedure (since these may cause image artifacts or other problems). Patients who take blood thinners or aspirin should talk to their physicians about whether they should discontinue using them prior to core needle biopsy. Any jewelry worn (especially earrings or necklaces) should be easily and quickly removable.

What Are the Advantages and Disadvantages to Core Needle Biopsy?

Core needle biopsy usually allows for a more accurate assessment of a breast mass than fine needle aspiration (if the sample is found to be solid or cloudy, suspicious-looking fluid) because the larger core needle usually removes enough tissue for the pathologist to evaluate abnormal cells in relation to the surrounding small sample of breast tissue taken in the specimen.

Nevertheless, core needle biopsy, like fine needle aspiration, only removes samples of a mass and not the entire area of concern. Therefore, it is possible that a more serious diagnosis may be missed by limiting the sampling of a lesion (abnormality).

A relatively new biopsy procedure called vacuum-assisted breast biopsy is able to remove approximately twice the amount of breast tissue compared with core needle biopsy while still offering the patient a minimally invasive breast biopsy procedure.

Updated: August 29, 2007