Core Needle Biopsy

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Overview

According to the United States National Cancer Institutes, core needle biopsy (or core biopsy) is the removal of a tissue sample with a wide needle for examination under a microscope.

I feel it’s imperative to explain a breast biopsy before diving deep into a core needle biopsy. A breast biopsy is a test carried out to remove tissue or, sometimes, fluid from the suspicious area of the breast. The removed tissue or fluid are then examined under a microscope and further tested to check for the presence of cancerous cells.

There are three types of biopsies, namely

• Fine-needle aspiration
• Core-needle biopsy
• Surgical biopsy

A core needle biopsy uses the procedure of removing a small amount of suspicious tissue from the breast with a large core (that is, hollow) needle. It is usually performed while the patient is under anaesthesia, meaning the breast is made numb. The procedure may require the doctor to insert a very small marker inside the breast to mark the location of the biopsy. The marker makes it easier for a surgeon to locate the abnormal area if surgery is later required, and even if no further treatment, like surgery, is needed, the marker makes it easier for a breast imaging radiologist to see on future mammograms the location where the biopsy was done.

Sometimes, no imaging equipment is needed, but this is only in cases where the lump can be felt through the skin. 

The core needle biopsy procedure can be used on most parts of the body. However, the most commonly used areas are – Lymph nodes, Breast, Prostate and Bone.

The core-needle biopsy procedure is associated with fewer side effects and can be used for

• Palpable mass. That is lumps that can be felt. 
• Non-palpable abnormal finding. That is suspicious areas that can only be seen on a mammogram or other imaging test.

Types of Core Needle Biopsy. 

There are a couple of core needle biopsy procedure – stereotactic core needle biopsy, and Vacuum-assisted core needle biopsy

• Stereotactic core needle biopsy.

For the stereotactic core needle biopsy procedure, a mammogram is used to take pictures from different angles in other to be able to pinpoint the biopsy site. The X-ray pictures of the breast are then analysed with the aid of a computer to know where exactly the needle tip needs to go in the abnormal area. This type of core needle biopsy procedure is usually used to biopsy suspicious tiny calcium deposits, small masses or other abnormal areas that can’t be clearly seen on an ultrasound.

• Vacuum-assisted core needle biopsy, VAB.

As regards the vacuum-assisted core needle biopsy, a hollow probe is inserted through a small cut into the abnormal area of breast tissue. The probe is guided in using an imaging test. A core of tissue is then suctioned into the probe, and a rotational knife inside the probe cuts out the tissue sample from the rest of the breast. 

For this procedure, several samples can be taken from the same cut and it usually removes more tissues.

Why you may be required to do a Core Needle Biopsy

You may be required to carry out a core needle biopsy for several reasons, some of which are – 

1. To diagnose a medical condition, or to rule out a disease or condition
2. To assess the progress of a treatment
3. If there are changes in your nipple, like a discharge or puckered skin
4. To establish the cause of an irregularity close to the chest wall, the nipple, or the surface of the breast

What you should likely expect during a core needle biopsy procedure

During a Core Needle Biopsy Procedure:

The first step is to properly position you to either sit up, lay flat or on your side, or lay facing down on a special table with openings for your breasts to fit into. However, you must be still while the biopsy is being done. After which a local anaesthesia is applied to numb your breast.

A small cut (of about a quarter, ¼, inch) is then made in the breast, through which the biopsy needle is put into the breast tissue to remove the tissue sample. Some pressure might be felt as this happens. However, to guide the needle to the right spot imaging tests may be used.

A clip (a tiny tissue marker) is then put into the area where the biopsy is done. This marker guides the mammograms or other imaging tests to aid the location of the exact area for follow up or further treatment, if needed. You, however, can’t feel or see the marker. It stays in place during the MRIs, and it will not set off metal detectors.

Once the tissue needed is removed, the needle is then taken out, and the area is covered with a sterile dressing. If need be, pressure may be applied for a short time to help reduce bleeding.

The core needle biopsy procedure itself is usually quick. The actual insertion and removal of the needle takes roughly about 1 minute but may be done more than once. The entire procedure usually takes about 15 to 30 minutes. 

However, it may take a longer time if imaging tests are needed. 

After the core needle procedure.

The first thing you may experience is some feeling of discomfort. This happens as the numbing medication starts to wears off. 

You may have to limit strenuous activities for a day or two. After which you will be able to go back to your usual activities. A small amount of bleeding may occur at the site of the biopsy.

In some cases, there may be a collection of a pocket of blood (that is, hematoma) in the area of the biopsy. This may be uncomfortable but it usually resolves in a couple of days.

You may likely develop some bruises or swelling after the procedure, and this may make it seem like the breast lump has become larger. There is no cause for alarm, and any bruising or swelling that may occur will go away over time, as a core needle biopsy doesn’t usually leave a scar.

Whatever the case might be your doctor or nurse will give you detailed information and necessary instructions. 

Results interpretation

After the core needle biopsy procedure, a pathologist (a doctor who specializes in the study of cells and tissue samples for signs of disease) will study the biopsy sample in the laboratory to make a diagnosis and create a pathology report for your doctor. 

The pathology report may include:

• A description of the biopsy sample: that is, a description of the biopsy sample in general. For example, a description of the colour and consistency of the tissues or fluid collected by the core needle biopsy procedure and an account of the number of slides were submitted for laboratory analysis.
• A description of the cells: that is, a description of how the cells appear under the microscope, the number of cells seen and what types of cells were seen. Also, it captures information on the special dyes that were used to understudy the cells in order to gather more information about the diagnosis and the best treatments regimen.
• The pathologist’s diagnosis: This lists the pathologist’s diagnosis. This may include comments, such as other tests that may be recommended.

These findings will determine the next steps to be taken in your medical care.

Advantages and limitations

Advantages 

• There’s accessibility to all breast areas. 
• It does not use ionizing radiation. 
• There’s low incidence of complications and discomfort for the patient. 
• It’s cost friendly.
• It provides accurate diagnosis.
• There’s a very little chance for infection or bruises. 
• It provides real time imaging.
• When cancer is diagnosed, the procedure provides important information such as tumour type and grade, hormone receptor status and HER2 status. This information provides vital guide for treatment.

Drawback or limitations 

• There may be difficulty in visualising the findings.
• The patient may be allergic to the anaesthesia given.
• The need for a new biopsy may arise. However, this happens only in selected cases. 
• The needle may miss the tumour and take sample of normal tissue instead. In this case, it gives a false negative result and delays diagnosis. However, this only happens when the procedure is done without an ultrasound, MRI or stereotactic mammography. 
• It may not be able to give full information about the tumor. Such as the size, and, sometimes, whether or not the tumour is non-invasive breast cancer (ductal carcinoma in situ) or invasive breast cancer.