When a physician commits to routine screening of women for breast cancer, he or she will be faced with abnormal findings that will require interpretation and further evaluation. Most findings will be benign, but the primary physician must order the appropriate additional tests and determine at what point specialty referral is necessary.

When a nonpalpable mammographic abnormality is found, there are several options for further evaluation: early mammographic follow-up and physical examination in 6 months, needle-localized excisional breast biopsy, and stereotactic or sonographic-guided core needle biopsy or fine needle aspiration. The best of these options depends on the degree of concern evident in the mammography report, patient and physician preference, and amenability of the lesion to the various different biopsy techniques.

In an attempt to standardize mammography reports and help gynecologists and primary physicians understand the radiologist's findings and recommendations, the American College of Radiology has devised a nomenclature, the Breast Imaging Reporting and Data System (BIRADS), for reporting mammography findings. The abnormal finding is assigned a BIRADS number, ranging from 0 through 5:

0 - Assessment is incomplete; additional imaging evaluation needed
1 - Negative finding
2 - Benign finding
3 - Probably benign; short follow-up interval suggested
4 - Suspicious abnormality; biopsy should be considered
5 - Highly suggestive of malignancy; appropriate action should be taken

A set of guidelines based on the BIRADS nomenclature was assembled to assist primary physicians in managing mammographic abnormalities. For categories 4 and 5, the guidelines recommend that the patient be referred to a surgeon immediately. For category 3, the primary care physician should order early interval imaging as recommended by the radiologist and also perform clinical examination at that time. For a category 0 finding, the physician should order the additional imaging studies needed to further evaluate the lesion.

Further, the guidelines point out that no further intervention is necessary for mammographic lesions that ultrasound has proven to be simple cysts. If an image-guided needle biopsy is performed, the pathologic result must agree with the radiographic finding. While these needle biopsies are highly accurate, the lesion can be sampled inadequately, so follow-up is always necessary.

Accurate staging of breast cancer Once breast cancer has been diagnosed, the patient must be accurately "staged" to plan treatment and determine their long-term prognosis. "Staging" simply means accurately determining the extent, severity, and spread of the cancer. Many parameters are used in determining "stage", including the size and characteristics of the tumor and whether or not it has spread to lymph nodes or other organs.

The patient's survival is related to tumor size and, more importantly, to nodal status (spread of the cancer to lymph nodes). When routine screening or mammography diagnoses breast cancers, most of these cancers are node-negative by clinical examination (physical examination shows no evidence of spread to the lymph nodes). Breast cancer patients who have no evidence of spread to the lymph nodes on physical examination are candidates for sentinel node biopsy. Identification, removal, and evaluation of the sentinel node(s) provides an alternative to complete removal of the axillary nodes (complete axillary dissection) and the complications that can accompany this more extensive surgical procedure. Sentinel node biopsy is currently investigational and should be performed by surgeons with extensive experience in the technique. Because of the additional pathologic evaluations that are performed on the sentinel node(s), this technique is less invasive but can yield more precise staging information than does the standard pathologic evaluation of an axillary dissection specimen.

The rationale for "sentinel" node biopsy depends on the predictable spread of the original cancer to the adjacent lymph nodes before it spreads elsewhere. The spread of cancer from the primary site can be "mapped" to identify the first lymph node or nodes to which the cancer will spread. Biopsy and pathologic evaluation of this node determines whether the cancer has spread beyond the "lump" itself. If the sentinel node is negative for cancer, removal of all of the axillary lymph nodes can be avoided. Focused pathologic examination with special stains can increase the accuracy of staging by identifying small tumor deposits in the sentinel node that might be missed during routine pathologic examination of multiple lymph nodes from a standard axillary dissection.

Injecting a radioactive "tracer" or a blue dye into or near the breast cancer tumor can identify the sentinel node(s). The first lymph node(s) that contain the radioactive tracer and/or blue dye are assumed to be those that are the first "drains" from the tumor. They (the sentinel nodes) would be the first to show evidence of spread of the breast cancer. If none is found in the sentinel node(s), it should be very unlikely that the tumor has spread further.

Evaluation of the "sentinel node" technique (without completion axillary dissection for sentinel node-negative patients) is ongoing in two national multicenter trials through the American College of Surgeons Oncology Group and the NSABP.

Accurate staging by these and other methods determines the necessity for chemotherapy, radiation therapy, and long-term chemoprevention. All of these factors, when precisely assessed, give the breast cancer patient reasonable information about therapy and prognosis.