Core Needle Biopsy - Evaluating a Possible Tumor

In order to provide a pathologist with a sample of a tumor, an interventional radiologist, oncologist, or surgeon will need to perform a biopsy. This can be done in various ways, such as with an excisional biopsy or a fine needle aspiration. The more tissue that is removed, the more accurate a diagnosis the pathologist can make. However, taking too much tissue may not be reasonable either. Sure the pathologist can make a very precise diagnosis of liver cancer if the entire liver is removed, but a person without a liver is not terribly healthy. Therefore a balance should be made between tissue removal and preservation. For many applications, a core needle biopsy is the method of choice.

 

 

Cancer is all about the cells. Almost everything that a pathologist can learn about a cancer is determined by how the tumor cells look under a microscope. Certain structures within the cells (called organelles) change when a cell is cancerous and those changes can predict if the tumor is malignant or benign. Volumes of information can be gathered from these cells if the pathologist can see the tumor cells in relation to other cells that are around it. One of the primary questions that can be answered by seeing the cancer cells in context: are the cancer cells invading normal tissue?

 

A core needle biopsy provides a large number of cells in a chunk, so to speak, so that the cancer cells can be examined in relation to other cells and tissues. During a core needle biopsy, a relatively large diameter needle (~14 gauge) is advanced into the core of the tumor. Much like coring an apple, once the needle is removed, the center of the core needle is filled with tissue. This can be extruded and studied. The sample obtained from a core needle biopsy can also be used to test for various molecular markers—estrogen and HER2 receptors in breast cancer, for example—which can aid in making treatment decisions. However, the core needle biopsy must take tissue from the tumor, otherwise false negative results may occur (a false negative is concluding that there is no disease when there really is disease).

 

Core needle biopsy procedures are commonly performed for breast cancer diagnosis but have been applied to various forms of cancer including prostate, thyroid, and even lymphoma. A core needle biopsy can be performed to make diagnoses other than cancer, as well. Liver cirrhosis and infiltrative heart disease are cases in which a core needle biopsy may be used for diagnostic purposes.

 

A core needle biopsy is usually performed through the skin after the nerve endings have been deadened with local anesthesia. In certain fibrous tissues, such as breast tissue, the core biopsy needle is spring loaded to help it penetrate the tissue between the surface of the body and the tumor itself. Since a larger amount of tissue is taken relative to a fine needle aspiration, anyone having a core needle biopsy must preemptively discontinue anticoagulant medications and be able to form blood clots effectively. A pressure dressing is usually applied afterward. In most cases, the loss of tissue from the area is not noticeable after the area is healed. An excisional biopsy, on the other hand, may leave a noticeable depression in the skin.