Large Core Needle Biopsy - Making The Diagnosis: Breast Cancer

Content provided by the Faculty of the Harvard Medical School

Large core needle biopsy

This method involves the use of a hollow needle to remove samples of breast tissue to be examined microscopically. Since the early 1990s, large core needle biopsy has been the diagnostic method of choice to evaluate abnormalities that are visible on a mammogram but cannot easily be felt by hand. In the more advanced medical centers, it is considered the standard of care.

Large core needle biopsy can be performed using either mammographic (stereotactic) or ultrasound guidance. Mammographic calcifications are usually biopsied using the stereotactic method, whereas mammographic densities can be sampled by ultrasound guidance when the density is visible by ultrasound and by stereotactic guidance when the density is visible only by mammography.

To perform a large core needle biopsy, the doctor anesthetizes the skin and inserts a needle the thickness of a pen-tip into the breast. Using the mammogram or ultrasound images, or by feeling the lump, the doctor guides the needle into the area of concern and removes a tissue sample through the needle with the help of a vacuum. Core needle biopsy may cause some bruising but leaves only a tiny dot for a scar.

Core needle biopsy may not be suitable for patients who have an irregularity close to the chest wall, the nipple, or the surface of the breast; those with calcifications that require magnification; or women with very small breasts. In these circumstances, fine needle aspiration may be the preferred choice. Also, if a patient is anti-coagulated (taking blood thinners), the physician will take measures to minimize the possibility of bleeding following the procedure. In some of these situations, accurate results may not be possible and an open surgical biopsywill be recommended.

Stereotactic core needle biopsy. With this procedure, the mammographer or surgeon looks at a mammogram image while performing the biopsy in order to precisely locate the suspicious area. This method is useful when the doctor can see an abnormality on a mammogram but cannot feel it in a breast exam.

The patient lies face down on a specially designed table with the breast compressed. The doctor injects a local anesthetic, makes a 3-mm skin incision, and then inserts the core biopsy needle. Usually results are available within a day or two. Women who cannot remain still for 20-40 minutes because of physical illness or other problems are not good candidates for stereotactic core needle biopsy.

Ultrasound guided core needle biopsy. With this method, the radiologist uses ultrasound imaging to precisely confirm the location for biopsy with the core needle. The doctor makes only a single puncture in the skin to extract three to six separate core needle tissue samples for analysis. The patient may feel some pressure but no pain.

The procedure takes only a few minutes. Following the procedure, a bag of ice is placed on the site for 15 to 30 minutes, and most patients are able to resume normal activity almost immediately afterward. As indicated above, if the patient is anti-coagulated, modifications of the blood thinning medicines should be considered.

Results of core needle biopsy. In experienced centers, 65% of women who undergo this procedure have a benign diagnosis and can resume having annual mammograms. Another 25% of patients have a malignancy and proceed with treatment.

For the remaining 10% of patients, results are inconclusive. For these patients, the next step is often a type of biopsy known as an excisional biopsy.

If the core biopsy suggests atypical ductal hyperplasia, surgical biopsy can help determine if the abnormality is atypical hyperplasia (about 81%), DCIS (ductal carcinoma in situ at 13%), or an invasive breast cancer (in only 6%). If, on the other hand, the core biopsy demonstrates tissue changes known as atypical lobular hyperplasia, then excisional biopsy may not be necessary.

If lobular carcinoma in situ is found, several treatment options may be considered, such as

• Continued close follow up

• Long term treatment with an estrogen blocker (for example, tamoxifen)

• Bilateral mastectomies (rarely).

For patients whose core needle biopsy shows DCIS, the full lesion will need to be removed for further examination in the laboratory. For these patients, the likelihood of an invasive breast cancer ranges from 0% to 28%.

There are two additional considerations when using a large core needle biopsy. If the lesion is large, the breast surgeon may want to mark the area of biopsy with a clip that can be detected by mammography, especially if a subsequent larger biopsy is planned. It will also mark the area of the cancer and allow easier identification of the area if the patient undergoes additional treatments and an assessment of response is desired.

If the lesion is small, the clip will serve to mark the anatomic location of the breast abnormality, which on occasion can be removed entirely by the biopsy. Having this information will be useful if other treatments are considered, such as radiation.

Patients may ask whether the "needle tract" that is created by the needle biopsy can be "seeded" with cancer cells (thus potentially spreading the cancer cells along the needle tract), as the needle is withdrawn after the biopsy has been obtained. This is hypothetically possible and can be minimized by considering radiation treatment in those women who are not going to undergo a mastectomy and by selecting the shortest distance from the skin to the lesion.

Last updated:	April 23, 2007