A biopsy is a procedure in which a sample of tissue is removed from the breast to examine it for cancerous (malignant) cells under a microscope. A biopsy may be performed if a symptom of breast cancer is present, such as a lump, changes in the skin of the breast, or unusual nipple discharge. A biopsy may also be used in cases where an abnormal finding shows up in a mammogram, ultrasound, or MRI (magnetic resonance imaging) scan.1
There are several different types of biopsies that may be performed on the breast, including1:
The type of biopsy may be determined by several factors, such as the size and location of the abnormality, the general health of the patient, the patient’s preference, and if the location is able to be felt (palpable) or only visible on certain imaging. There are risks and benefits to each type of procedure. Patients should discuss their options with their healthcare professionals.2
Fine needle aspiration biopsy
A fine needle aspiration biopsy uses a very thin needle to remove fluid or a small amount of tissue from an area. It may be used for lumps that can be felt (palpable).1
Core needle biopsy
A core needle biopsy uses a hollow needle which can take a narrow sample of tissue, about the size of a grain of rice. Several samples may be taken at the time of the biopsy. Core needle biopsies may be used on palpable lumps or on an area that is found through mammography or ultrasound. If the area cannot be felt, the core needle biopsy may be used with imaging techniques to help position the needle correctly. (See ultrasound-guided biopsy and MRI-guided biopsy below.)1
A stereotactic biopsy is guided using mammography and may be used in cases where the suspicious area is visible on a mammogram. During a stereotactic biopsy, the patient is either seated or lying face down on a biopsy table with the breasts fitting into an opening in the table. The breast is compressed in the mammogram machine to find the area, and samples are taken using a needle or vacuum-powered probe.1
Ultrasound is an imaging technique that uses sound waves to view internal structures in the breast. During an ultrasound-guided biopsy, the patient is lying down, and the radiologist uses the ultrasound machine to locate the suspicious area. Samples are taken using a core needle biopsy.1
MRI an imaging test that uses powerful magnets and radio waves to generate 3-dimensional pictures of the structures inside the breast. During an MRI-guided biopsy, the patient lays face down on a table with the breasts fitting into an opening in the table. The MRI helps the radiologist locate the suspicious area, and samples of tissue are removed using a core needle biopsy.1
A surgical biopsy also called an open biopsy, is performed under general anesthesia. Surgical biopsies may be incisional, in which a portion of the lump is removed, or excisional, in which the entire lump and potentially a surrounding layer of normal cells are removed, then checked for the presence of cancer cells. (An excisional biopsy may also be called a lumpectomy.)1
Lymph node biopsy
The lymph nodes under the arm, called the axillary lymph nodes, may also be biopsied to see if breast cancer has spread to the lymph system or if there is a swollen lymph node that is suspicious. A lymph node biopsy may be done with a needle biopsy (either fine needle or core), a sentinel lymph node biopsy, or an axillary lymph node dissection.2 A sentinel lymph node biopsy removes just the first lymph node(s) in the chain of lymph nodes. A radioactive dye, and/or blue dye, is inserted in the breast and used to identify the sentinel node(s), which is removed during surgery. An axillary lymph node dissection is a surgical procedure in which several lymph nodes (typically anywhere from 10 to 40) under the arm are removed. In addition to pain and swelling from a surgical procedure, people who have had a lymph node surgery are at an increased risk of developing lymphedema, a swelling in the affected arm or chest area.3
After a biopsy
After needle biopsies, a tiny metal clip may be placed into the breast at the site of the biopsy. This metal clip provides a marker to locate the site of the biopsy if additional procedures are needed (if the biopsy comes back as cancerous, or malignant).1
Needle biopsies commonly cause bruising, and patients may need over-the-counter pain medication (like acetaminophen) or an ice pack to ease the discomfort (patients should discuss options for safely treating their potential pain with their healthcare professional). Surgical biopsies often require stitches, which require additional care.1
The tissue samples from a biopsy are sent to a pathology lab for examination. It may take several days before the results are available, and this waiting time can be a time of high anxiety. The pathology report will be sent to the patient’s doctor, who will share the results with the patient.1
Breast biopsy. Mayo Clinic. Available at https://www.mayoclinic.org/tests-procedures/breast-biopsy/about/pac-20384812. Accessed 8/29/18.
Breast biopsy. American Cancer Society. Available at https://www.cancer.org/cancer/breast-cancer/screening-tests-and-early-detection/breast-biopsy.html. Accessed 8/29/18.
Lymph node surgery for breast cancer. American Cancer Society. Available at https://www.cancer.org/cancer/breast-cancer/treatment/surgery-for-breast-cancer/lymph-node-surgery-for-breast-cancer.html. Accessed 8/29/18.