Breast cancer: Breast biopsy

A biopsy is the removal of cells or tissue from a suspicious mass. The tissue or cells are then examined under a microscope to check for cancer cells. A biopsy may be performed when an abnormal breast change is found during a mammogram, ultrasound or physical examination. A biopsy is the only way to determine if a potential trouble spot is cancerous or benign.

There are many types of biopsy procedures. The method recommended by your doctor will depend on how large the breast lump or abnormal area is, where in the breast it is located, how many lumps or abnormal areas - such as suspicious calcifications - are present, if you have any other medical problems and what your personal preferences are.

What are the types of biopsies?

The types of biopsies include:

• Needle aspiration. A non-surgical form of breast biopsy in which a small needle is used to withdraw a sample of cells from the breast lump. If the lump is a cyst (fluid-filled sac), removal of the fluid will cause the cyst to collapse. If the lump is solid, cells can be smeared on to slides for examination.
• Needle biopsy. Similar to needle aspiration, but a larger needle is used because actual breast tissue is removed rather than a tiny sampling of cells. A sample of the lump is removed, but not the entire lump. An ultrasound scan or a series of X-rays may be used by the doctor to guide the needle to the exact location.
• Surgical or excision biopsy. Surgical removal of the entire lump. The tissue is then studied under a microscope. If a rim of normal breast tissue is taken all the way around a lump (called a lumpectomy), then the biopsy can also serve as part of breast cancer treatment (removal of the cancerous tumour). This is sometimes done with wire localisation. In this technique a wire is inserted through a needle into the area to be biopsied. An X-ray is taken to make sure it is in the right place. A small hook at the end of the wire keeps it in position. The surgeon uses this wire as a guide to locate the abnormal tissue to be removed.
• Sentinel lymph node biopsy. A newer biopsy method can be used to pinpoint the first lymph node into which a tumour drains (called the sentinel node) and remove only the nodes most likely to contain cancer cells. To locate the sentinel node a radioactive tracer, a blue dye or both are injected into the area around the tumour before a mastectomy is performed. The tracer travels the same path to the lymph nodes that the cancer cells would take, making it possible for the surgeon to determine the one or two nodes most likely to test positive for cancer.

Cells or tissues that are removed using any of the methods described above are given to a pathologist, a doctor who specialises in diagnosing abnormal tissue changes.