A screening mammogram is done when a woman has no symptoms of breast disease and has a normal clinical breast exam (CBE). Screening mammograms are usually performed by mammogram technicians, include two views, and are read by a radiologist at a later time.

• Sensitivity of screening mammograms is > 85%
  Sensitivity is defined as the ability of a test to correctly identify someone who has the disease. This is the percentage of true positives or a positive mammogram in a woman who actually has breast cancer.
• Specificity of screening mammograms is > 90%
  Specificity is defined as the ability of a test to correctly identify someone who does not have the disease. This is the percentage of true negatives or a negative mammogram in a woman who does not have breast cancer.

A diagnostic mammogram is usually the recommended follow-up for women with any of the following:

• Breast symptoms (a lump or pain)
• An abnormal clinical breast examination (a palpable mass)
• Suspicious findings from a screening mammogram

A diagnostic mammogram can also be used as the initial breast cancer screening for women with any of the following:

• Breast implants (mammogram with additional implant displaced views)
• Scarring from previous chest surgery
• A history of a previous abnormal mammogram

A diagnostic mammogram is performed in the presence of a radiologist and includes multiple views. It focuses on the specific area of the breast that is in question. Often, a radio-opaque marker is placed over the abnormal area to further focus the mammogram.

BI-RADS (Breast Imaging Reporting and Data System) - the BI-RADS reporting system was developed in 1998 by the American College of Radiology (ACR) to standardize the description of abnormalities on mammograms. The BI-RADS reporting system was updated in 2003 and was also adopted for the reporting of breast ultrasounds.

Breast ultrasound is a non-invasive method for imaging the breast that does not deliver any radiation and is not usually accompanied by any discomfort. Breast ultrasound is used as an adjunct to a mammogram or for a physical finding, and can be helpful in differentiating solid tumors and fluid-filled cysts. Ultrasounds are reported using the American College of Radiologists BI-RADs assessment categories as discussed above (ACR, 2003b).

Breast ultrasound can be used for the following:

• Follow-up of a mass seen on a mammogram, especially to help differentiate solid from cystic masses.
• Follow-up of a palpable mass or asymmetrical skin thickening/nodularity in a woman under 30 years. An ultrasound is frequently used for younger women because of their lower incidence of breast cancer and greater density of breast tissue.
• As a part of the imaging for some breast biopsy procedures.

Breast cysts are a common cause of palpable breast masses in pre-menopausal women. Cystic lesions in postmenopausal women are uncommon and should be viewed as suspicious, and referred to a breast specialist. The ability to aspirate suspected cysts in the primary care office can be very useful to help differentiate a fluid-filled cyst from a solid mass, such as a benign fibroadenoma. Both masses often have the clinical appearance of a smooth, mobile isolated mass.

A syringe and thin needle are used to remove fluid and/or cells from the suspected cyst:

• If non-bloody fluid is returned and if the mass disappears after aspiration, then the likelihood of malignancy is very low and the woman can be followed up in 1-2 months.
• Bloody or cloudy fluid can mean a benign cyst or less frequently, cancer, and should be sent for cytology.
• If fluid cannot be aspirated or if the mass persists after aspiration, follow-up for a palpable mass should be used (Lucas, 2003).

Fine Needle Aspiration (FNA) of a breast mass: FNA by an experienced professional can be very useful as part of the management of a persistent palpable breast mass. For non-palpable masses, image-guided biopsies are used in the diagnostic management (see below).

The triple test is a diagnostic technique for palpable abnormalities of the breast and it includes: Clinical breast exam, Diagnostic mammogram, and Fine needle aspiration (FNA).

• This triple test is considered positive if any one of the components has positive findings (suspicious or malignant).
• The triple test is negative only when all three components are negative (benign).
• On average, if the triple diagnostic technique is negative for findings, there is a negative predictive value of > 99% (Morris, et al, 2001).

Fine needle aspiration by an experienced professional is performed with a 20-25 gauge needle while the mass is stabilized with the clinician's non-dominant hand. The technique is similar to that of breast cyst aspiration. However, if no fluid is returned, ultrasound may be used to help guide the needle placement and the needle can be moved up and down through the mass 20 times while applying negative pressure to the syringe. The needle is then withdrawn and any cellular material is deposited on a slide, a fixative is added, and it is sent for pathology (Zuber, 2004).

Stereotactic core needle biopsy and ultrasound-guided biopsy are increasingly being used by breast specialists as the initial biopsy for breast masses instead of surgical biopsy. The tissue specimens are sent to pathology for review.

A stereotactic core needle biopsy is a biopsy technique that combines visualization of the mass with mammogram guidance and a computer-assisted visualization in three dimensions. Stereotactic biopsies are usually done with larger needles than Fine Needle Aspiration and are used to collect 6 to 12 core specimens under local anesthesia. Most of the time, a woman lies prone on a table. Her breast is placed through a hole in the table and immobilized. The radiologist then uses a computer-generated, three-dimensional view of the breast to identify the area to be biopsied (ACS, 2004).

An ultrasound-guided needle biopsy uses ultrasound to guide needle placement for the core biopsy and is used when masses are difficult to palpate on clinical exam or see from the mammogram. At least 4 specimens are collected and local anesthesia is used (NCI, 2004).

An excisional biopsy removes the entire lesion as well as a surrounding margin of normal tissue. This is usually in the hospital outpatient setting and with local anesthesia and sometimes with imaging to help locate the suspicious mass or calcifications.

An incisional biopsy removes a sample of the mass or suspicious area. The tissue specimens from both excisional and incisional biopsies are sent to pathology for review (ACS, 2004).

Breast magnetic resonance imaging (MRI) is becoming very important in further evaluation of abnormal mammograms and for local and regional staging of already diagnosed breast cancer. The MRI is not evidence-based for breast cancer screening at this time.

The MRI can be more sensitive than traditional mammograms in characterizing some breast lesions (e.g., invasive breast cancer), but can be less sensitive in detecting other lesions (e.g., ductal carcinoma in situ). The MRI is also less specific than a mammogram, e.g., the ability to discriminate between benign lesions, normal breast tissue and suspicious lesions. And the MRI is significantly more expensive and less available than mammograms for follow-up of a palpable breast mass (Zuber, 2004).

According to the American College of Radiology, there are a number of indications for use of the breast MRI as listed in the table below:

Positron Emission Tomography (PET) scans are metabolic images that can be helpful as an adjunct imaging method for local and regional staging of already diagnosed breast cancer. PET scans, combined with CT scanning, are used in delineating breast cancer margins and the degree of disease to help surgeons plan appropriate procedures. PET scans may also be helpful in women with very dense breasts, significant fibrocystic changes, or fibrosis after radiotherapy when mammograms and MRI are difficult to interpret (Zuber, 2004).

Ductal lavage is an investigational procedure that can be used to try to identify early cellular changes that indicate a high risk of breast cancer development in high-risk women. It is not evidence-based for breast cancer screening at this time. Nipple aspiration is first used to locate the milk ducts, and then a catheter is inserted into a duct with a small amount of anesthetic and then saline. The fluid is then aspirated and sent for pathology review.

If atypical cells are returned from the lavage, a woman has an increased risk of developing future breast cancer (Relative Risk of 3-5) (Newman, 2004). A recent study found that cancer cells were detected with the ductal lavage screen in only 50% of the study women already diagnosed with breast cancer (Khan, 2004). Research is continuing on the usefulness of ductal lavage for early detection in women at high risk for breast cancer.

Breast thermography is a technique that creates thermal images of the breast. It is based on the assumption that a malignancy will have increased blood vessel formation and heat production compared to normal breast tissue. However, there is no evidence to support the use of this test as a stand-alone screening method or as a diagnostic adjunct in detecting breast cancer, since it misses some cancers and can give a high positive rate (ACS, 2003).