Core biopsy

A core biopsy uses a hollow needle or probe to remove tissue from the body. When a needle is used, it is called a core needle biopsy.

The tissue removed during a core biopsy comes out as a long, narrow piece (called a core). As a result, the structure of the tissue remains intact. This gives the doctor more information about the abnormal area and helps them decide whether or not further tests or treatments are needed. This is an advantage over a fine needle aspiration (FNA), which doesn’t preserve the structure of the tissue. If the structure is not preserved, a doctor may be able to see cancer cells but can’t see what the tissue surrounding the cancer looks like.

A core biopsy can be done on most areas of the body, but it is most often used to remove tissue from an abnormal area of the prostate, breast or lymph nodes.

Why a core biopsy is done

Your doctor may do a core biopsy if they find an abnormal area during a physical exam or on an imaging test, such as an x-ray or ultrasound. A core biopsy is used to:

  • check for cancer
  • find out the type of tumour
  • find out the grade of cancer

How a core biopsy is done

A core biopsy is done in a doctor’s office, clinic or hospital. In most cases, you don’t need to do any special preparation and the procedure takes about 15–30 minutes.

The doctor uses a local anesthetic to freeze the area. Then they pass the hollow needle or probe into the abnormal area. The doctor will usually take several samples of tissue during the biopsy. The samples are sent to a lab to be looked at under a microscope.

If the doctor can feel the abnormal area, they can use a physical exam to help guide the needle or probe. If they can’t feel the abnormal area, the doctor will use an ultrasound, x-ray, MRI or a CT scan to help guide the needle or probe.

Special types of core biopsy

Stereotactic core needle biopsy and vacuum-assisted core biopsy are special types of core biopsy. They are most often used to help diagnose breast cancer.

Stereotactic core needle biopsy

A stereotactic core needle biopsy is used to take samples from an abnormal area of the breast that doctors can see on an imaging test but can’t feel. Before doing the biopsy, the doctor uses x-ray images of the breast (mammograms) and a computer to create a 3-D picture of the abnormal area. This helps the doctor find the exact location of the abnormal area and guide the needle during the biopsy. Sometimes a small piece of metal is placed in the biopsy area so that it can be easily found if the doctor has to look at it again later.

Vacuum-assisted core biopsy

This type of core biopsy uses a special vacuum inside the probe to remove more tissue than a standard core biopsy. The doctor starts by making a small cut (incision) in the skin to pass the probe through. They may use x-rays, an ultrasound or an MRI to guide the probe through the cut into the abnormal area. A rotating knife inside the probe cuts the tissue and pulls it inside the probe.

Side effects

Side effects of a core biopsy depend on where the biopsy is done. For example, men who have a core biopsy of the prostate will have different side effects than women who have a core biopsy of the breast. In general, side effects may include:

  • bleeding or bruising
  • tenderness
  • pain
  • infection

Sometimes a vacuum-assisted core biopsy may leave a small scar.

What the results mean

A pathologist will look at the tissue sample under a microscope. The pathology report describes the types of cells in the sample, what they look like and if they are normal or abnormal and if they contain cancer.

Depending on the result, your doctor will decide if you need more tests, any treatment or follow-up care.

Special considerations for children

Preparing children before a test or procedure can lower anxiety, increase cooperation and help them develop coping skills. Preparation includes explaining to children what will happen during the test, including what they will see, feel, hear, taste or smell.

Preparing a child for a core biopsy depends on the age and experience of the child. Find out more about helping your child cope with tests and treatments.

Expert review and references