How is Breast Cancer Diagnosed?

A lump or other changes in your breast, or an abnormal area on a mammogram, may be caused by cancer or by other, less serious problems.

Click here to read the American Cancer Society's Screening Guidelines

Breast Examination by a Physician

To determine the cause of any signs or symptoms, your physician will perform a thorough physical exam that includes a personal and family medical history as well as evaluate your current overall health status. In addition, an examination may include the following:

  • Palpation: Carefully feeling the lump and the tissue around it - its size, texture, and whether it moves easily. Benign lumps often feel different from cancerous ones.
  • Nipple discharge examination: Fluid may be collected from spontaneous nipple discharge and then sent to the lab to look for cancer cells. Most nipple secretions are not cancer, because an injury, infection, or benign tumor may cause discharge.


Your physician may also perform an imaging test such as a diagnostic mammogram, ultrasound or MRI.

  • Diagnostic mammogram with digital mammography (also called full-field digital mammography, or FFDM) uses an X-ray of the breast to diagnose unusual breast changes, such as a lump, pain, nipple thickening or discharge, or a change in breast size or shape. A diagnostic mammogram is also used to evaluate abnormalities detected on a screening mammogram. It is a basic medical tool and is appropriate in the workup of breast changes, regardless of a woman's age.

Digital mammography is a type of mammography in which the images are electronically captured and stored on a computer, rather than X-ray film. The images are viewed on a computer screen. Images can be changed, including the degree of magnification, brightness or contrast, to help visualization. They can also be transmitted electronically.

Digital procedure currently costs more than standard mammography. Studies are being done to see which type of mammography will be of more benefit to women for the long term. Some studies have found FFDM to be more accurate in finding cancers in women younger than 50. Also, it has been found that women undergoing digital mammography do not have to return for additional studies as often as with standard mammography because the digital images have fewer questionable spots needing further investigation. However, not all hospitals and mammography facilities have digital equipment available.

  • Ultrasound. Uses high-frequency sound waves that do not emit radation. This test is done to further evaluate lumps felt in the breast or identified on mammagram.
  • Magnetic resonance imaging (MRI). Uses a combination of powerful magnets, radiofrequencies, and a computer to create detailed images of your breast.


If these tests reveal any abnormal findings, a biopsy will be performed to determine if cancer or other abnormal cells are present. Using a special biopsy needle, a small sample of breast tissue or cells are removed for further examination. Biopsies may be performed under local or general anesthesia.

There are several types of breast biopsy procedures and their use will depend upon the location and size of the breast lump or abnormality. Types of breast biopsy procedures include, but are not limited to, the following:

  • Fine needle aspiration biopsy (FNA): A very thin needle is placed into the lump or suspicious area to remove a small sample of fluid and/or tissue. No incision is necessary. A fine needle aspiration biopsy may be performed to help to differentiate a cyst from a lump.
  • Core needle biopsy : A large needle is guided into a lump or suspicious area to remove a small cylinder of tissue (also called a core). No incision is necessary.
  • Surgical biopsy (also called an open biopsy) : A surgeon removes part or all of a lump or suspicious area through an incision into the breast. There are two types of surgical biopsies. During an incisional biopsy, a small part of the lump is removed; whereas during an excisional biopsy, the entire lump is removed. In some cases, if the breast lump is very small and deep and is difficult to locate, a special wire is placed into the lump under X-ray guidance. The surgeon follows this wire to help locate the breast lump.
  • Sentinel node biopsy : This procedure is used to determine the spread of cancer cells to the lymph nodes, usually axillary. This surgical procedure may be performed during the initial diagnostic period to aid in staging the breast cancer. This procedure involves injecting a dye and/or radioactive substance near the tumor. This injection helps to locate the lymph node closest to the tumor (sentinel node) - the one that is most likely to have cancer cells present if the cancer has spread. The surgeon removes the lymph node that absorbs the dye and radioactive substance and sends it to the pathologist to examine it for the presence of cancer cells.

There are special instruments and techniques that may be used to guide the needles and to assist with biopsy procedures. These include, but are not limited to, the following:

  • Stereotactic biopsy: Finds the exact location of a breast lump or suspicious area by using a computer and mammogram results to create a 3-D image of the breast. A sample of tissue is removed with a needle.

  • The following techniques use a stereotactic approach:
  • Vacuum-assisted breast biopsy system : A tube-like structure is inserted into the breast lump or mass. The breast tissue is gently suctioned into the tube, and a rotating knife removes the tissue.
  • Ultrasound-guided biopsy : Ultrasound technology is used to help guide the radiologist to the site of the breast lump or mass.