When imaging tests suggest the presence of cancer, a biopsy will usually be needed to confirm. This procedure involves removing a sample of tissue from a patient that can then be observed under a microscope and run through various tests. The main types of breast biopsies are fine needle aspiration (FNA) biopsy, core needle biopsy (CNB), and surgical biopsy (also known as open biopsy).[1]

A FNA biopsy uses a syringe with a small, hollow needle to aspirate a small amount of tissue or fluid from the suspicious area. If a lump can be felt, the doctor can guide the needle by touch. If a lump cannot be easily felt, however, the doctor might use an ultrasound to guide the procedure. A FNA biopsy is the simplest type of biopsy because it is quick and does not require any incisions, so no stiches are needed. However, a FNA biopsy could miss a cancer if the needle is incorrectly placed or not enough cancer cells are aspirated. Second biopsies may be needed in some cases. For a FNA biopsy, local anesthetic could be used but is typically not needed because the needle is so thin.[2]

A CNB is typically the preferred method of biopsy is breast cancer is expected because it removes more tissue than a FNA biopsy but does not require surgery. A CNB uses a hollow needle to aspirate tissue from a suspicious area using a spring-loaded tool that quickly moves the needle in and out of the tissue or using a suction device. Typically, several small cylinders (cores) of tissue are removed. The doctor may place the needle by feeling the lump, but an imaging test such as an ultrasound, MRI, or mammogram is usually needed to guide the procedure. A small tissue marker (clip) is usually put into the biopsy area afterward so the area can be located by imaging tests if further treatment is needed. A CNB is usually done under local anesthesia.[3]

There are also special types of CNBs such as stereotactic CNB and vacuum-assisted biopsy (VAB). A stereotactic CNB uses mammogram images from different angles to pinpoint the suspicious area. This is typically used for very small masses that cannot be seen clearly with ultrasound imaging. A VAB uses a hollow probe placed through a small cut into the suspicious area. An imaging test is used to guide the probe, and then a core of tissue is suctioned into the probe and cut off using a rotating knife. A VAB removes more tissue than a standard CNB, and several tissue samples can be taken from one cut.[3]

A surgical biopsy may be performed in some situations such as if a needle biopsy came back inconclusive. A surgical biopsy removes part of or all of the suspicious area during an operation. This type of biopsy may be excisional meaning the entire suspicious area and often a small margin of surrounding tissue is removed or incisional meaning only part of the suspicious area is removed. Preoperative localization may be done using an ultrasound, mammogram, or MRI to guide the surgeon to the suspicious area if a lump cannot be easily felt. This involves placing a wire or other localizing device such as radioactive seeds, magnetic seeds, or a radiofrequency reflector into the suspicious area. When a wire is used, this procedure may be called stereotactic wire localization. A surgical biopsy may be performed under local anesthesia with IV sedation to make the patient drowsy or under general anesthesia to put the patient to sleep.[4]

References

1.     Breast Biopsy https://www.cancer.org/cancer/breast-cancer/screening-tests-and-early-detection/breast-biopsy.html (accessed Jun 22, 2021).

2.     Fine Needle Aspiration (FNA) Biopsy of the Breast https://www.cancer.org/cancer/breast-cancer/screening-tests-and-early-detection/breast-biopsy/fine-needle-aspiration-biopsy-of-the-breast.html (accessed Jun 22, 2021).

3.     Core Needle Biopsy of the Breast https://www.cancer.org/cancer/breast-cancer/screening-tests-and-early-detection/breast-biopsy/core-needle-biopsy-of-the-breast.html (accessed Jun 22, 2021).

4.     Surgical Breast Biopsy https://www.cancer.org/cancer/breast-cancer/screening-tests-and-early-detection/breast-biopsy/surgical-breast-biopsy.html (accessed Jun 22, 2021).