Biopsy is a technique used to extract cells from tissue in order to get a better understanding (i.e., diagnosis) of the types of cells or the state of the health of the tissue (e.g.: whether the a mass is benign or malignant). After the biopsy sample is removed, it is sent to a laboratory for further evaluation under the microscope.
If imaging tests (such as mammography) show a suspicious-looking mass, your doctor will order a biopsy. The removal of cells from the mass is done by one of four methods:
• Fine needle aspiration biopsy (FNAB) uses a very thin needle to collect fluid or cells directly from the mass. Usually, the doctor can perform this procedure while feeling the lump to help guide the needle. If a mass that was seen on a mammogram cannot be felt easily, the doctor may use ultrasound or computer-guided imaging to help locate the mass and guide the position of the needle. Use of computer-guided imaging to help locate the mass and guide the position of the needle is called stereotactic needle biopsy.
If this procedure locates fluid, it is an indication that the lump is a cyst. If the procedure locates a solid mass, a biopsy sample of the mass will be removed and sent to a laboratory for further analysis under the microscope. Solid masses can be malignant.
Using FNAP, mammography, and a clinical breast exam, a doctor can determine with about 98% accuracy whether a lump is benign or malignant. If, however, there is still doubt, a core needle biopsy may be ordered.
• Core needle biopsy uses a larger needle to remove a small cylinder of tissue from the lump and send it to a laboratory for further analysis under the microscope.
• Incisional biopsy involves surgical removal of just a portion of the mass, which is sent to a laboratory for further analysis under the microscope.
• Excisional biopsy involves surgical removal of the entire mass, which is sent to a laboratory for further analysis under the microscope.
Currently, approximately 80% of the results of biopsies from the breast that were performed because of an abnormal clinical breast examination or abnormal mammogram show that the abnormality is not cancer. A biopsy from the breast can result in any of the following diagnoses:
• The lump or previously suspicious area is normal tissue, and is nothing to worry about. A lump of normal tissue represents one of several natural changes that the breast can undergo over time. Even if tests indicate that the lump is nothing to be concerned about, it is still important to be diligent about your monthly self breast exams, clinical breast exams, and mammograms (performed annually if you are over 40).
• The lump or previously suspicious area is not cancer, but you need to be re-checked in 4 to 6 months to make sure that there have not been any changes in the tissue.
• The lump or previously suspicious area is not cancer, but it is abnormal. Often such a diagnosis can mean that you may have a condition that puts you at higher risk of developing breast cancer in the future. If this is the case, your doctor may require that you get more frequent clinical breast exams.
• The lump or previously suspicious area is cancerous. In this case, your doctor will talk to you about the different treatment options available. Because treatment options usually depend on the type and characteristics of the cancer, your doctor usually will order additional tests to learn more about your cancer.
For example, the cells extracted during your biopsy often are screened for an abnormality called HER-2 overexpression. HER-2 overexpression occurs in about 25% of all breast cancers. If your breast tumor is HER-2-positive and shows HER-2 overexpression, your breast cancer may respond well to an antibody-based drug, called Herceptin (generic name, trastuzumab), which targets the HER-2 protein receptor on the surface of HER2-positive breast cancer cells.
1. M. Hitti. Biopsy best after abnormal mammogram. WebMD Medical News. 02/09/06. Accessed at www.webmd.com.