Causes and Diagnoses

Causes and Diagnoses of Breast Cancer

Lumps or other changes in your breast may be caused by cancer cells, but more often these abnormalities are caused by less serious conditions.

Diagnosis of breast cancer may include a physical exam that includes personal and family medical history, and an evaluation of your current overall health.

Your exam may also include:

  • Palpation: Careful feeling of the lump and the tissue around it (its size, its 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. For women who are at high risk for breast cancer, a procedure called ductal lavage may be used. This procedure collects cells from inside the milk ductal system.

Imaging tests for breast cancer

In addition to a physical exam by your physician, the following imaging tests may be done:

Diagnostic mammography

A diagnostic mammogram is an X-ray of the breast used 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 look closely at changes detected on a screening mammogram.

Digital mammography (full-field digital mammography or FFDM)

A type of mammogram 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 and can be changed to see them better. It's been found that women undergoing digital mammography typically don't have to return for additional studies as often as with standard mammography because the digital images are clearer.


Ultrasounds use high-frequency sound waves to get images of body tissues. The sound waves enter the breast and bounce back. The pattern of their echoes produces a picture called a sonogram, which is displayed on a screen. This exam is often used along with mammography.


A specialized radiology procedure sometimes used to assess the breasts when other examinations have not been clear. Scintimammography, or a molecular breast scan, is a type of nuclear radiology procedure, whereby a tiny amount of a radioactive substance (absorbed by body) is used to assist in the examination of the breasts.

Magnetic resonance imaging (MRI)

A diagnostic procedure that uses a combination of large magnets, radiofrequencies and a computer to produce detailed images. According to the American Cancer Society, contrast-enhanced MRIs have been shown to have a high sensitivity for detecting breast cancer in women.


A biopsy removes tissue or cells from the body so that they can be examined under a microscope. A biopsy is the only way to know for sure if cancer or other abnormal cells are present.

Biopsies can be done using a needle to get a piece of the area of concern, or they can be done with surgery.

Biopsies may be done under local or general anesthesia. Local anesthesia means drugs are used to numb the area of the breast that the needle will be put into. With general anesthesia, you will be given drugs to put you into a deep sleep while the biopsy is being done. There are several types of breast biopsy procedures. The type of biopsy done will depend on the location and size of the breast lump or abnormality.

Types of breast biopsy procedures include, but are not limited to:

  • Fine needle aspiration biopsy: 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 used to help find out if a breast change is a cyst (a fluid-filled sac that may often be benign and not malignant) or 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, the wire localization technique may be used during surgery. With this technique, a special wire is placed into the lump under X-ray guidance. The surgeon then follows this wire to help locate the breast lump.

Biopsy instruments and techniques

There are special instruments and techniques that may be used to guide the needles and to assist with biopsy procedures, including:

  • Stereotactic biopsy: Stereotactic biopsy finds the exact location of a breast lump or suspicious area by using a computer and mammogram results to create a three-dimensional picture of the breast. A sample of tissue is removed with a needle.
  • Mammotome breast biopsy system or ATEC (Automated Tissue Excision and Collection; also called vacuum-assisted biopsy): A type of hollow tube is inserted into the breast lump or mass. The breast tissue is gently suctioned into the tube, and a rotating knife inside the tube removes the tissue.
  • Ultrasound-guided biopsy: A technique that uses a computer and a transducer that sends out ultrasonic sounds waves to create images of the breast lump or mass. This technique helps to guide the needle biopsy.
  • Sentinel node biopsy: Used to see if cancer cells have spread to the lymph nodes. This surgical procedure may be done sometime after the biopsy during the initial diagnostic period to aid in staging of the breast cancer. This procedure involves injecting a dye and/or radioactive substance into the tumor. This injection helps to locate the lymph node that the tumor drains into first (the 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 closely for the presence of cancer cells.

Based on these exams, your physician may decide no further tests are needed and no treatment is necessary. In such cases, your physician may want to check you regularly to watch for any changes.