A breast biopsy is a diagnostic procedure where a small tissue sample is removed from the breast to be examined under a microscope. This process helps determine the nature of suspicious breast changes, such as lumps or abnormal findings on imaging tests. While the prospect of a biopsy can be concerning, it is a common procedure, and many biopsies reveal findings that are not cancerous.
Why a Biopsy Might Be Recommended
A healthcare provider recommends a breast biopsy when imaging tests or a physical examination identify an area of concern. Abnormal findings on mammograms, ultrasounds, or MRIs are frequent reasons for a biopsy recommendation. These can include suspicious masses, tiny calcium deposits known as calcifications, or distortions in the breast tissue’s normal structure.
A new lump or a persistent lump discovered during a physical breast exam also often prompts a biopsy. Other indicators include unexplained nipple discharge, particularly if it is bloody, or skin changes on the breast, such as dimpling, scaling, or crusting. A recommendation for a biopsy does not automatically mean cancer is present. Approximately 75% to 80% of breast biopsies result in non-cancerous findings. The biopsy provides a precise diagnosis, informing next steps.
Understanding the Biopsy Procedure
The specific method chosen depends on the characteristics of the suspicious area. Common types include:
Fine-needle aspiration (FNA): Uses a very thin needle to withdraw fluid or cells, often for palpable lumps or cysts.
Core needle biopsy (CNB): Employs a slightly larger, hollow needle to collect small cylinders of tissue, typically guided by ultrasound, mammography, or MRI, and multiple samples are usually taken.
Vacuum-assisted biopsy (VAB): Uses suction to pull tissue into a hollow needle, allowing for the collection of more samples with a single insertion, which is often used for microcalcifications.
Surgical biopsy: Also known as an excisional or incisional biopsy, involves a surgeon making a cut to remove part or all of the suspicious area. This procedure is usually performed in an operating room, sometimes with local anesthesia and sedation, and in some cases, a wire or seed is placed beforehand to guide the surgeon to the exact location.
Before the procedure, patients are often advised to avoid blood-thinning medications and aspirin. Most needle biopsies are outpatient procedures, performed with local anesthesia to numb the breast. A small marker clip may be placed at the biopsy site. After the biopsy, minor bruising and discomfort are common, and patients are typically advised to avoid strenuous activity for a day or two.
Interpreting Biopsy Results
After a breast biopsy, the tissue samples are sent to a pathologist, a specialist who then provides a detailed report. The results fall into one of three categories: benign, malignant, or atypical/high-risk. A benign result means no cancer cells were found. Common benign conditions include fibroadenomas, which are solid but non-cancerous growths, and cysts, which are fluid-filled sacs. Fibrocystic changes, involving fibrous tissue and small cysts, and fat necrosis, a healing response to injury, are also common benign findings that do not require further treatment.
A malignant result indicates the presence of cancer cells, and the report will specify the type of breast cancer, such as ductal carcinoma or lobular carcinoma. This diagnosis prompts a discussion about further treatment steps. Atypical or high-risk lesions are not cancerous themselves but signal an increased chance of developing breast cancer in the future. Examples include atypical ductal hyperplasia (ADH), where cells in the milk ducts show unusual patterns, and atypical lobular hyperplasia (ALH). While not cancer, these findings warrant closer monitoring, and sometimes surgical removal is recommended to reduce future risk.
When a Biopsy Isn’t the Next Step
Not every suspicious finding on breast imaging leads directly to a biopsy. In some situations, a healthcare provider may determine that a biopsy is not immediately necessary. This occurs when initial imaging findings are clearly benign, such as simple cysts, which may only require routine follow-up. Sometimes, an ambiguous finding on one type of imaging might prompt a recommendation for additional imaging, such as a different view or another type of scan like an MRI, before proceeding with a biopsy.
For findings that have a very low suspicion of malignancy, a healthcare provider might suggest short-term follow-up imaging to observe if the area changes or resolves. This approach avoids an invasive procedure when the likelihood of cancer is minimal. The decision to perform a biopsy is carefully considered, balancing the need for definitive diagnosis with avoiding unnecessary procedures.