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Evaluation of Breast Disorders
Breast symptoms (eg, masses, nipple discharge, pain) are common, accounting for > 15 million physician visits/yr. Although > 90% of symptoms have benign causes, breast cancer is always a concern. Because breast cancer is common and may mimic benign disorders, the approach to all breast symptoms and findings is to conclusively exclude or confirm cancer.
Principles of examination are similar for physician and patient. Breasts are inspected for asymmetry in shape, nipple inversion, bulging, and dimpling (see see Figure: Breast examination.A and B for usual positions). Although size differential is common, each breast should have a regular contour. An underlying cancer is sometimes detected by having the patient press both hands against the hips or the palms together in front of the forehead (see see Figure: Breast examination.C and D). In these positions, the pectoral muscles are contracted, and a subtle dimpling of the skin may appear if a growing tumor has entrapped a Cooper ligament. The nipples are squeezed to check for a discharge and determine its source (eg, whether it is multiductal).
The axillary and supraclavicular lymph nodes are most easily examined with the patient seated or standing (see see Figure: Breast examination.E). Supporting the patient’s arm during the axillary examination allows the arm to be fully relaxed so that nodes deep within the axilla can be palpated.
The breast is palpated with the patient seated and again with the patient supine, the ipsilateral arm above the head, and a pillow under the ipsilateral shoulder (see see Figure: Breast examination.F). The latter position is also used for breast self-examination; the patient examines the breast with her contralateral hand. Having the patient roll to one side, so that the breast on the examined side falls medially, may help differentiate breast and chest wall tenderness because the chest wall can be palpated separately from breast tissue.
The breast should be palpated with the palmar surfaces of the 2nd, 3rd, and 4th fingers, moving systematically in a small circular pattern from the nipple to the outer edges (see see Figure: Breast examination.G). Precise location and size (measured with a caliper) of any abnormality should be noted on a drawing of the breast, which becomes part of the patient’s record. A written description of the consistency of the abnormality and degree to which it can be distinguished from surrounding breast tissue should also be included. Detection of abnormalities during physical examination may mean that a biopsy is needed, even if imaging shows no abnormalities.
Imaging tests are used for screening and for evaluation of breast abnormalities.
Screening mammography is recommended yearly for women ≥ 50 yr and usually yearly or every 2 yr for women ≥ 40 yr (see page Breast Cancer : Screening). Mammography is more effective in older women because with aging, fibroglandular tissue in breasts tends to be replaced with fatty tissue, which can be more easily distinguished from abnormal tissue. Low-dose x-rays of both breasts are taken in 1 (oblique) or 2 views (oblique and craniocaudal). Only about 10 to 15% of abnormalities detected result from cancer. Accuracy of mammography depends partly on the techniques used and experience of the mammographer; false-negative results may exceed 15%. Some centers use computer analysis of digitized mammography images to help in diagnosis. Such systems are not recommended for stand-alone diagnosis, but they appear to improve sensitivity for detecting small cancers by radiologists.
Diagnostic mammography is used to evaluate masses, pain, and nipple discharge. It can determine size and location of a lesion and provide images of surrounding tissues and lymph nodes. Diagnostic mammography requires more views than screening mammography. Views include magnified views and spot compression views, which provide better visualization of suspect areas. Mammography can also be used to guide biopsy and, after surgery, to image the breast and the excised mass to help determine whether excision was complete.
Ultrasonography can be used to diagnose breast abnormalities and to stage breast cancer. If mammography detects one or more masses, ultrasonography is used to further evaluate them (eg, to determine whether they are solid or cystic). Ultrasonography is also used to evaluate abnormalities detected by MRI. Ultrasonography can be used before staging to identify abnormal axillary nodes that may require core biopsy.
MRI can be used to diagnose breast abnormalities and, before surgery, to accurately determine tumor size, chest wall involvement, and number of tumors. MRI is also used to identify abnormal axillary lymph nodes (to help stage breast cancer). For women at high risk of breast cancer (eg, with a BRCA gene mutation or a calculated lifetime risk of breast cancer of ≥ 15 to 20%), screening should include MRI in addition to clinical breast examination and mammography. MRI is not considered appropriate for screening women with average or slightly increased risk.
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