Breast Biopsy

Most providers will recommend a biopsy of any distinct and persistent lump even if there is no abnormality on breast imaging.

A biopsy is the removal of a sample of tissue from the breast for examination under a microscope, and is the only way to tell if cancer is really present. Most biopsies are now performed by a radiologist in the Breast Imaging Center rather than by a surgeon in the operating room.

Which biopsy technique to use will depend upon the woman’s individual situation. Your provider will consider how suspicious the abnormal tissue is, how large the area is, where in the breast it is located, other medical problems you may have, and your personal preferences in making a recommendation.

Discuss the advantages and disadvantages of different biopsy types with your provider.

Types of Biopsy

Core Biopsy
Core biopsy is the preferred method to obtain a tissue sample of any suspicious lesion. Core biopsy may be performed with either ultrasound or mammographic guidance in the Breast Imaging Center, depending upon which technique reveals the lesion.

Virginia Mason has been performing the core biopsy procedure since 1993 and was among the first facilities in the Pacific Northwest to offer this more comfortable, less invasive, less costly technique for women.

Excisional Biopsy
An excisional biopsy is a surgical procedure to remove an entire breast abnormality, as well as a surrounding margin of normal-appearing breast tissue for microscopic examination. This procedure is usually performed in the operating room.

When a tumor cannot be felt by the surgeon, intraoperative ultrasound may be used to locate its position prior to a biopsy. Another option is mammographic- or ultrasound-guided wire localization performed on the day of the operation before the operation is performed. During this procedure, the radiologist guides a thin wire into the breast tissue to pinpoint the area of concern. Once the tumor is removed, the pathologist examines the tissue and an x-ray of the tissue may be taken to ensure that the tumor has been removed with a rim of normal tissue around it.

The tissue sample taken during the biopsy is sent to a pathologist who examines the tissue under a microscope, looking for cells that show signs of cancer.

Biopsy Results
If cancer is found, the pathology report will identify aspects of the tumor’s characteristics that are important in determining the type of treatment that is right for you. Ask your provider to tell you what each item in the report means, including:

  • Size and location of the tumor: Size is reported in centimeters or millimeters.

  • Margins: This description will indicate if there is a rim of normal tissue around the tumor.

  • Type of tumor: A tumor will be described by type, such as ductal or lobular, and also as invasive (capable of spreading) or noninvasive (also called in situ).

  • Grade of the tumor cells: The grade is an indication of how fast cancer cells divide. Grade I is least aggressive. Grade III is most aggressive.

  • Estrogen and progesterone receptor status: Receptors are molecules that are a part of cells. Normal breast cells and some breast cancer cells have receptors that recognize estrogen and progesterone. Often, breast cancers that contain estrogen and progesterone receptors are referred to as ER-positive and PR-positive tumors. This may affect the type of treatment a woman receives.

    Women with ER-positive and PR-positive tumors are more likely to respond to treatment with the drug tamoxifen, which blocks the effects of estrogen in the breast. While estrogen has not been found to cause cancer, it may stimulate the growth of breast cancer cells. Thus tamoxifen is often described as an “anti-estrogen.”

  • Her-2/neu oncogene: Approximately 30 percent of breast tumors have excessive amounts of this oncogene. Oncogenes are specific stretches of DNA that, when activated in the wrong way, contribute to the transformation of normal cells into malignant ones.

    Tumors with the Her-2/neu oncogene may be a more aggressive type of cancer and may direct your oncologist to recommend particular types of chemotherapy.