Abstract
An internationally recognized staging system -- the TNM system -- has been adopted by both the Union Internationale Contre le Cancer and the American Joint Commission on Cancer Staging and End-Results Reporting.100 This system is based on the extent of the tumor, the involvement of the lymph nodes, and the presence of metastases (Table 3). Because the clinical evaluation of axillary-node involvement has high false positive and false negative rates, pathological staging based on histologic evaluation of the axillary specimen provides a more accurate assessment of prognosis for the individual patient than does clinical staging. The pathological stage is commonly given as stage 1 (no involvement of the axillary nodes, or node-negative) or stage 2 (involvement of the axillary nodes, or node-positive). Because the prognosis is clearly related to the extent of axillary involvement, it has become conventional to categorize patients according to the number of nodes involved -- that is, no positive nodes (node-negative), 1 to 3 positive nodes, 4 to 9 positive nodes, and 10 or more positive nodes. Because of the distribution of the lesion in the breast, it is useful to resect a segment of the breast including, when feasible, a portion of the adjacent subareolar region. Because of the very low incidence of axillary-node involvement, an axillary dissection is not indicated for localized lesions. "147 A second research issue is whether an axillary dissection is necessary, especially in patients with clinically negative axillae who will be treated with conservative surgery and irradiation. Since the primary purpose of axillary dissection is to guide the use of adjuvant systemic therapy, this surgery may be reasonably avoided in patients who are selected for adjuvant therapy on the basis of other factors -- for example, a postmenopausal woman with an estrogen-receptor--positive tumor measuring 2 cm will most likely be advised to take tamoxifen regardless of the findings on axillary dissection.
