Fine needle aspiration (also known as fine needle biopsy) is a needle biopsy that removes cells rather than tissue from an abnormal area in the breast. The needle used is thinner than in core needle biopsy. Fine needle aspiration is only used for suspicious areas that can be felt (palpable masses).
The procedure can be done in your health care provider's office. Although core needle biopsy is most often the first choice for palpable masses, fine needle aspiration is sometimes done as a quick way to sample a breast lump felt during a clinical breast exam. In the procedure, your provider may use a small amount of local anesthetic to numb the area and will then insert the needle and remove a sample of cells. The whole procedure takes only a few minutes.
Advantages of fine needle aspiration
Fine needle aspiration is accurate when done by an experienced health care provider (and read by an experienced cytopathologist). The procedure is quick, fairly inexpensive and only mildly uncomfortable. It does not involve surgery and only rarely leads to problems, such as infection or bruising. Finally, if the abnormal area was considered unlikely to be cancer before the biopsy, a benign test result means you will likely not need a more invasive surgical biopsy.
Drawbacks of fine needle aspiration
One drawback of fine needle aspiration is that the needle can miss a tumor and take a sample of normal cells instead. If this happens, the biopsy will show that cancer does not exist when in fact it does. This is called a false negative result and can delay diagnosis. When combined with a clinical breast exam and a mammogram, the false negative rate of fine needle aspirations of palpable masses (those that can be felt) is about five percent [5]. Sometimes, even if the correct area is sampled, the procedure may not remove enough cells to be able to tell if they are cancerous. Therefore, a fine needle aspiration that does not find cancer may need to be followed up with another type of biopsy, like a core needle or surgical biopsy.
Another drawback of fine needle aspiration is that the cell samples give limited information about the tumor. For example, they often cannot tell whether a tumor is ductal carcinoma in situ or invasive cancer. And, the cells removed by fine needle aspiration must be checked by an experienced breast cytopathologist (a physician who specializes in examining cells under a microscope). This can be a drawback because some hospitals do not have a cytopathologist.
Updated 10/26/09
