Ask Dr. K: Type of breast biopsy varies from patient to patient

What your doctor saw was a spot that looked like it might be cancer. The mammogram, and other breast-imaging techniques such as magnetic resonance imaging (MRI), cannot tell with certainty. If the mammogram looks suspicious, a biopsy is the only way to know for sure if there is a cancer.

In a biopsy, a part of the suspicious-looking area is removed by a minor surgical procedure. This tissue is analyzed in a lab to determine whether it is cancerous and, if so, how quickly it is likely to grow and spread. This information helps to guide treatment decisions.

A breast biopsy can be done in different ways, depending on the location and size of the abnormality and other factors.

— A doctor can perform fine needle aspiration (FNA) in an office by inserting a slender needle into the breast and drawing out (aspirating) a small amount of tissue from a suspicious lump. The doctor may aspirate several samples.

In some cases, the doctor may use ultrasound images to guide the needle. Ultrasound shows when the tip of the needle has reached the suspicious area. Ultrasound has no damaging effects on the breast: Unlike a mammogram, ultrasound does not involve any radiation.

— Most doctors prefer the large core needle biopsy method because it removes more tissue, and that makes for a more accurate diagnosis. A larger needle than the one used for FNA is used. The needle is inserted into the breast through a tiny incision. Using X-rays or ultrasound images as a guide, or by feeling the lump, the doctor moves the needle into the area of concern. He or she extracts one or more tissue samples through the needle using suction from a syringe.

Stereotactic needle biopsy is a type of large core needle biopsy. It uses special imaging equipment to pinpoint the tissue to be removed.

— In a surgical biopsy, the surgeon makes an incision and removes all or part of the abnormal tissue for examination. It is done in an operating room under local or general anesthesia. A biopsy that removes only part of the suspicious tissue is called an incisional biopsy. One that removes the entire lump is called an excisional biopsy.

Sometimes a surgical biopsy is preceded by wire localization. During a mammogram, a radiologist inserts a small wire through a needle into your breast, with the end of the wire inside the suspicious area. This helps the surgeon more easily identify the suspicious area during the surgical biopsy.

Most biopsies reveal that the suspicious area of the breast is not cancer. Until the biopsy is done, a woman and her family and friends are understandably concerned. But most of the time, the news turns out to be good.

Dr. Komaroff is a physician and professor at Harvard Medical School. To send questions, go to AskDoctorK.com, or write: Ask Doctor K, 10 Shattuck St., Second Floor, Boston, MA 02115.