A biopsy — a small sample of tissue removed for analysis in the laboratory — is the only test that can tell if cancer is present. Biopsies can provide important information about an unusual breast change and help determine whether surgery is needed and if so, the type of surgery required. Types of biopsies include:
§ Fine-needle aspiration biopsy. Your doctor uses a thin, hollow needle to withdraw tissue from the lump. He or she then sends the tissue to a lab for microscopic analysis. The procedure takes about 30 minutes and is similar to drawing blood. A similar procedure — fine-needle aspiration — is typically performed to remove the fluid from a painful cyst, but it can also help distinguish a cyst from a solid mass.
§ Core needle biopsy. A radiologist or surgeon uses a hollow needle to remove tissue samples from a breast lump. As many as 15 samples, each about the size of a grain of rice, may be taken then sent to a pathologist to be analyzed for malignant cells. The advantage of a core needle biopsy is that it removes more tissue for analysis. Sometimes your radiologist or surgeon may use ultrasound to help guide the placement of the needle.
§ Stereotactic biopsy. This technique is used to sample and evaluate an area of concern, such as microcalcification, that can be seen on a mammogram but that cannot be felt or seen on an ultrasound. During the procedure, a radiologist takes a core needle biopsy, using your mammogram as a guide. Stereotactic biopsy usually takes about an hour and is performed using local anesthesia.
§ Wire localization. Your doctor may recommend this technique when a worrisome lump is seen on a mammogram but can't be felt or evaluated with a stereotactic biopsy. Using your mammogram as a guide, a thin wire is placed in your breast and the tip guided to the lump. Wire localization is usually performed right before a surgical biopsy and is a way to guide the surgeon to the area to be removed and tested.
§ Surgical biopsy. This remains one of the most accurate methods for determining whether a breast change is cancerous. During this procedure, your surgeon removes all or part of a breast lump. In general, a small lump will be completely removed (excisional biopsy). If the lump is large, only a sample will be taken (incisional biopsy). The biopsy is generally performed on an outpatient basis in a clinic or hospital.