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Diagnosis of Breast Cancer
Diagnostic Evaluation of Breast Cancer
Electrical Impedance Imaging - This procedure assesses the electrical conductivity of the breast, based on the idea that breast cancer cells conduct electricity better. It involves passing a very small electrical current through the body and detecting it on the skin of the breast with a small probe (similar to an ultrasound probe). The test does not use radiation or require breast compression. This test has received FDA approval to be used as a diagnostic aid in helping classify tumors detected by mammography. However, it has not undergone enough clinical testing to recommend its use in breast cancer screening.
Biopsy for Suspected Breast Cancer
A biopsy is performed to remove a tissue sample for examination under a microscope when a suspicious lesion is found on mammogram, ultrasound or physical examination. There are several types of biopsies, and each has advantages and disadvantages. The choice of which type of biopsy procedure to use depends on the individual situation. Some of the deciding factors include:
- Size of the lesion
- How suspicious the lesion appears
- Where the lesion is located in the breast
- How many lesions are present
- If co-existing medical problems are present
- Personal preference of the patient
- Experience of the surgeon
Approaches to Breast Biopsy
The options for performing a breast biopsy include:
Fine needle aspiration biopsy (FNAB) - This type of biopsy uses a very thin needle which is guided into the area of the breast abnormality. If the lump can not be felt easily, the doctor might use ultrasound or a method called stereotactic needle biopsy to guide the needle. With ultrasound, the doctor can watch the needle on a screen as it moves toward and into the mass. For stereotactic needle biopsy, computers map the exact location of the mass using mammograms taken from two angles. Once the needle is in place, fluid or small tissue fragments are drawn out. These samples are then sent to the lab, where they are examined under the microscope. Microscopic examination of FNAB samples can tell whether most breast abnormalities are benign or cancerous. In some cases, FNAB does not provide a clear answer and another type of biopsy is needed.
Triple Test - This is not an actual test or procedure. It is a way of correlating the results of the breast physical examination, mammogram, and the FNA biopsy. If all three of these appear benign, the lesion can indeed be considered to be benign with about 98% accuracy. If any one of these is in disagreement, more tests (needle core biopsy or surgical biopsy) should be done.
Core needle biopsy (CNB): The needle used in a core biopsy is larger than that used in FNA biopsy. It removes a small cylinder of tissue (about 1/16 inch in diameter and 1/2 inch long) from a breast abnormality. The biopsy is done with local anesthesia in the doctor's office. As with FNA biopsy, a core biopsy can sample abnormalities felt by your doctor as well as smaller ones pinpointed by ultrasound or stereotactic methods. Two types of special devices used for taking a core biopsy are:
