What is a biopsy?

A biopsy is the removal of cells or tissue from a suspicious mass. The tissue or cells are then examined under a microscope to detect cancer cells. A biopsy may be performed when an abnormal breast change is found during a mammogram, ultrasound, or physical examination. A biopsy is the only way to determine if cancer or a benign breast condition is present.

There are many types of biopsy procedures. The type of biopsy recommended by your physician will depend on how large the breast lump or abnormal area is; where in the breast it is located; how many lumps or abnormal areas, such as suspicious calcifications, are present; if you have any other medical problems; and what your personal preferences are.

What are the different types of biopsies?

    * Fine needle aspiration (FNA): This is a non-surgical form of breast biopsy in which a small needle is used to withdraw a sample of cells from the breast lump. If the lump is a cyst (fluid-filled sac), removal of the fluid will cause the cyst to collapse. If the lump is solid, cells can be smeared onto slides for examination in the laboratory.
    * Core biopsy: This is similar to FNA, but a larger needle is used because actual breast tissue, rather than a sampling of cells, is removed. A sample of the lump is removed, but the whole lump is not removed. The advantage of this biopsy is that more information may be obtained because more tissue is removed. Since it was performed under some type of imaging, it is also more accurate. The types of core biopsies include ultrasound-guided core biopsy and stereotactic core biopsy.
    * Ultrasound-guided core biopsy: This tissue sampling technique does not require surgery. A small opening may be made in the skin. A biopsy needle is placed into the breast tissue. Ultrasound helps confirm the needle placement using sound waves reflected off breast tissue so the exact location of breast tissue is biopsied. The type of echo varies with each type of tissue. Ultrasound can distinguish many benign lesions, such as fluid-filled cysts, from solid lesions. Tissue samples are then taken through the needle.
    * Stereotactic core biopsy: With this technique, the area to be biopsied is centered in the window of a specially designed compression paddle. First, mammogram films, called scout films, are taken so the radiologist can examine the breast tissue to be biopsied. Using a local anesthetic, the radiologist makes a small opening in the skin. A sterile biopsy needle is placed into the breast tissue area to be biopsied. Computerized pictures help confirm the exact needle placement using digital imaging. Tissue samples are taken through the needle. It is common to take multiple tissue samples (about three to five).
    * Open excisional biopsy: This is the surgical removal of the entire mass. The tissue is then studied under a microscope. If a rim of normal breast tissue is taken all the way around a lump (lumpectomy), the biopsy can also serve as part of breast cancer treatment.
    * Sentinel node biopsy: This is a new biopsy method used to pinpoint the first few lymph nodes into which a tumor drains (called the sentinel node) and to remove only the nodes most likely to contain cancer cells. To locate the sentinel nodes, a radioactive tracer and/or blue dye is injected into the area around the tumor before a mastectomy is performed. The tracer travels the same path to the lymph nodes that the cancer cells would take, making it possible for the surgeon to determine the one to three nodes most likely to test positive for cancer. If the nodes are positive for cancer, then more lymph nodes are usually removed and a full axillary dissection is performed. Performing his method varies among surgeons, but sentinel node biopsy is offered at most breast centers.

Tissue or cells that are removed are given to a pathologist, a physician who specializes in diagnosing abnormal tissue changes.