In rare cases when a mammogram, breast ultrasound or MRI can’t quite rule out breast cancer, a breast biopsy may be necessary. In a biopsy, cells or tissue from a concerning area in the breast are removed for an experienced pathologist to examine. These tissue samples help doctors determine with more certainty whether or not cancer is present.
There are several types of biopsies used to diagnose breast cancer. A patient may need a needle biopsy, a surgical biopsy or both depending on the amount of tissue needed to confirm a diagnosis.
In a needle biopsy, a physician uses a hollow needle to remove tissue or cell samples from the breast. There are two types of needle biopsies that can be used to study lumps that can be felt (palpable masses) as well as those only visible in a mammogram or other imaging tests (non-palpable masses).
- Core Needle Biopsy – A core needle biopsy is usually the preferred method for examining a mass in the breast that can be felt. When done by an experienced radiologist, this procedure is accurate, quick and does not require surgery. If a core needle biopsy shows cancer is present, the extracted tissue sample usually provides important information – such as hormone receptor status and the tumor type and grade – which can help guide the patient’s treatment plan.
- Fine Needle Aspiration Biopsy – Fine needle aspiration biopsy (FNAB) is generally only used to examine palpable masses. Like core needle biopsy, this procedure can be done in your physician’s office in just a few minutes with a very small chance of infection or bruising. FNAB uses a smaller needle and is a less invasive procedure than core needle biopsy. This method also usually produces accurate results when conducted by an experienced physician and checked by an experienced cytopathologist (a physician who specializes in checking cells under a microscope).
- Magnetic Resonance Imaging (MRI) Guided Biopsy – For suspicious areas that can only be found by MRI, biopsy may be guided by an MRI machine. In this method, the patient lays face down on a specially designed table with an opening for the breasts. Computers are used to help locate the tumor and guide the probe into it.
The main drawback of needle biopsies is the possibility of the needle missing the tumor and returning a sample from normal tissue instead. If that happens, the procedure could produce a false negative result, meaning it does not detect cancer where cancer does, in fact, exist.
A surgical biopsy involves cutting the breast open to remove all or part of a suspicious lump from the breast so the tissue can be examined under a microscope.
- Excisional Biopsy – In most biopsies that require surgery, the entire suspicious area along with some surrounding normal tissue are removed from the breast in what is called an excisional biopsy or lumpectomy. Before the operation, patients are usually given a local anesthetic and IV sedation to help them through the procedure. If the lump is not palpable and was first detected by an imaging test, a radiologist will then use a mammogram or breast ultrasound to guide a thin wire into the area to be biopsied; this wire will guide the surgeon to the designated area during surgery.
If the area removed during the procedure shows that cancer is present, a pathologist will then look at the amount of normal tissue surrounding the tumor to determine if all of it has been taken out. While the goal of excisional biopsy is to diagnose or rule out breast cancer, there are instances when a surgeon might be able to remove all of the cancer through excisional biopsy alone. In other cases, however, another surgery to remove the lymph nodes may be needed.
- Incisional biopsy – An incisional biopsy is done in rare cases to take out only part of a tumor that may be too large to remove in entirety. This procedure is very similar to an excisional biopsy. However, since only part of the tumor is removed in an incisional biopsy, more surgery might be needed to remove any remaining cancer.
In many cases, core needle and fine needle biopsies could be done right in the physician’s office with local anesthesia. Needle biopsies very rarely leave scars inside or outside the breast, and the chances of infection or bruising are also very small. Hence, physicians will usually suggest trying a needle biopsy first before resorting to surgery.
On the other hand, surgical biopsies are the most accurate ways of diagnosing breast cancer and can provide the most complete information about the tumor. The down side is that, compared to needle biopsies, surgical methods will be more invasive, require more recovery time and pose a higher risk of infection and bruising. Because more tissue is removed in excisional and incisional biopsies, these procedures may also change the look and feel of the breast.
In any case, any concerns about a lump in the breast should be discussed with an experienced physician or specialist who can help determine which type of biopsy and treatment would be best for each individual patient.
Dr. Renita Butler is a Radiology specialist who sees current and new patients at Kelsey-Seybold’s Main Campus. Her clinical interests include breast imaging, sports medicine and ankle and foot pathologies.