Fine needle aspiration (also known as fine needle biopsy) removes cells from a suspicious lump in the breast. The needle used is thinner than in core needle biopsy.
Fine needle aspiration is only used for lumps that can be felt (palpable masses). 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.
A fine needle aspiration can be done in your health care provider's office. Before the procedure, your provider may use a small amount of local anesthetic to numb the area. He/she will then insert the needle and remove a sample of cells. The whole procedure only takes a few minutes.
Advantages of fine needle aspiration
Fine needle aspiration is accurate when done by an experienced provider and read by an experienced cytopathologist (a physician who specializes in checking cells under a microscope).
The procedure is less uncomfortable than a core needle biopsy and the chance of infection or bruising is very small.
If the lump was not thought to be cancer before the fine needle aspiration, a benign (not cancer) test result means you will likely not need a 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 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 lumps that can be felt is about five percent .
Sometimes, even if the correct area is sampled, the procedure may not remove enough cells to be able to tell if they contain cancer. So, a fine needle aspiration that does not find cancer may need to be followed up with a core needle biopsy or a 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 breast cancer. The cells removed by fine needle aspiration must also be checked by an experienced breast cytopathologist, and not all hospitals have a cytopathologist.