In an excisional biopsy, the whole abnormal area, plus a layer of nearby normal tissue, is removed. The procedure is done in an operating room by a surgeon. It is most often done using a local anesthetic to numb the area that will be biopsied. You will get IV sedation rather than general anesthesia. Most people who have an excisional biopsy do not need to stay overnight in the hospital.
Excisional biopsy is not part of standard medical care for palpable breast masses (those that can be felt). Excisional biopsy may be used for non-palpable masses (those that cannot be felt and can only be seen on a mammogram). Before surgery, a procedure called wire-localization or needle-localization will be done. During this procedure, a radiologist uses a mammogram or ultrasound image as a guide to insert a very thin wire into the suspicious area of the breast. The surgeon then uses this wire to find the area during surgery.
The breast tissue that is removed is most often X-rayed. This lets the surgeon and radiologist match the suspicious areas on a mammogram with those in the biopsy tissue. If the areas match, the correct tissue was removed. If the areas do not match, the surgeon may try again to remove the correct tissue or may wait to do another biopsy.
Although the goal of an excisional biopsy is to diagnose cancer, the procedure can also be considered treatment if the surgeon finds cancer and completely removes it. In some cases, excisional biopsy may be the only surgical treatment needed to remove a cancerous breast tumor. For others, lymph nodes may also need to be removed. Learn more about breast cancer treatment.
Frozen sections
In some cases, part of the tissue sample removed during biopsy is frozen. This frozen section allows the pathologist to cut off a thin slice and check it under the microscope to see if it is cancerous. Although a frozen biopsy section can give a quick check of the tissue sample, it has a high rate of false negative results [5]. For this reason, the results always need to be confirmed by other methods, which can take about two working days.
The standard way to treat a tissue sample is called formalin fixed paraffin embedded tissue. The tissue sample is treated with a substance called formalin, which hardens the tissue and prevents the tissue from breaking down over time.
Assessing margins
If the biopsy shows cancer, a pathologist will test the tumor to decide whether there is enough normal tissue surrounding it. This margin of normal tissue helps show whether all of the abnormal tissue was removed. Clean (also called "uninvolved" or "negative") margins mean that there is only normal tissue at the edges of the tissue removed, and no further surgery is needed. If cancer cells extend to the edge of the sample or there is not a large enough area of normal tissue surrounding the tumor, these are called "involved" or "positive" margins. In these cases, more surgery is done to get clean margins.
Advantages of excisional biopsy
Surgical biopsy is accurate and gives few false negative results. A false negative result is one that says cancer is not present when in fact it is. Excisional biopsy also can determine a tumor's size, type, grade and hormone receptor status. (Learn more about these factors.) Such information helps plan treatment.
Excisional biopsy can also serve as treatment for breast cancer. It may be the only surgery needed to remove the tumor.
Drawbacks of excisional biopsy
Excisional biopsy is more invasive than a needle biopsy. The recovery time is longer and more uncomfortable and there is a greater risk of infection and bruising. The amount of tissue removed can also change the look and feel of the breast. If you have excisional biopsy and the biopsy results are benign (not cancerous), then you may have had more surgery than needed.
Updated 10/26/09
