If cancer is suspected, a biopsy will be performed. This involves removing tissue and examining it under a microscope for cancerous cells. There are a number of approaches to the biopsy procedure, each of which is designed to obtain accurate results with minimal discomfort.
Thanks to imaging methods such as ultrasound and stereotactic mammography, doctors can use minimally invasive procedures such as fine needle and core needle biopsy to diagnose breast lumps even if you can't feel them.
During an ultrasound examination, the physician can view the needle on a screen as it moves toward and into the mass. Stereotactic needle biopsy is a useful method when the lump is visible on a mammogram but not felt. Based on mammograms taken from two angles, a computer maps the lump’s precise location. A small electric motor controlled by the computer guides the placement of the needle for core needle or, less often, fine needle biopsy.
Fine Needle Biopsy
In a fine needle biopsy, fluid and cells are taken from the suspicious lump through an extremely thin needle. If primarily fluid is removed, it means the lump is most likely a cyst and the removal of the fluid will make the lump disappear. If cells are extracted, a pathologist will look at them to see if they are benign or cancerous.
Sometimes, a local anesthetic is applied to the breast to numb the area before the needle is inserted. For this type of biopsy, there is no need to make a cut in the breast. If the lump can't be felt, ultrasound or stereotactic images may be used help the doctor pinpoint the abnormality. If the abnormality is a fluid-filled cyst, it is usually benign, but can be drained and a sample analyzed for definitive diagnosis.
Core Needle Biopsy
In a core needle biopsy, a hollow needle is inserted into the lump and a portion of the tissue is taken out for evaluation. A local anesthetic is applied to the breast to numb the area before the needle is inserted. Only a very tiny cut is needed to insert the core needle. This cut is so small that no sutures are required to close it.
If the lump can't be felt, ultrasound, stereotactic images, or MRI may be used to help the doctor pinpoint the abnormality.
The advantages of this procedure are many. It is less traumatic than an open surgical biopsy and you will have a much smaller scar than with open surgical biopsy. For those with negative results (non-cancerous tumors), a surgical biopsy is usually not necessary. A tiny radiologic marker is usually placed into the breast biopsy site at the time of the core needle biopsy.
Wire-Localized Breast Biopsy
The role of the wire-localized surgical (excisional) breast biopsy is to help the surgeon pinpoint the correct area in your breast for biopsy. Wire localization is a procedure used to guide a surgical (excisional) breast biopsy when the lump or abnormality is difficult to feel. After numbing the area with a local anesthetic, a hollow needle – thinner than that used for drawing blood – is placed into the breast using X-rays to guide the needle to the suspicious area. When the tip is in the correct position, a small amount of blue dye is injected through it. After the needle is removed or replaced with a wire, you will be taken in for your biopsy. The surgeon uses the wire or the dye as a guide to locate the abnormal area to be removed. If recommended, the wire localization is performed immediately prior to your surgical breast biopsy.
In an incisional biopsy, the surgeon cuts out a sample of a lump or suspicious area to determine if the lump is benign or cancerous. This type of biopsy is done only when the lump is so large that the breast would need to be removed entirely (mastectomy), or complete removal of the lump is not necessary or would result in cosmetic deformity. The disadvantage to this type of biopsy is that the entire lump has not been removed. If it is cancerous, it will usually require additional treatment or surgery.
In an excisional biopsy, the surgeon removes all of the lump or suspicious area. A pathologist then examines the tissue under a microscope to check for cancer cells. In some cases, this procedure also functions as a lumpectomy, with no further surgery needed.
Stereotactic Breast Biopsy
The purpose of a stereotactic breast biopsy is to obtain a tissue sample from the area of abnormality identified on your mammogram. Digital images of the breast are taken from several angles and a computer calculates the exact location of the lump.