Updates in Management of Axilla in Breast Cancer

Abstract

A major milestone in the management of breast cancer over the past decade has been the transition from axillary lymph node dissection (ALND) to sentinel node biopsy (SNB) for the detection of axillary lymph node metastases. This shift has triggered a reassessment of the goals, outcomes, morbidity, and alternatives to ALND. ALND has historically performed two important roles: (a) staging of the axilla by detection of nodal metastases; (b) tumor control in the axilla. The tumor control achieved by axillary node dissection can be an important element in patient prognosis. Meta-analyses have supported that the local control achieved by ALND can impact disease-free survival, and salvage treatment of an axillary recurrence results in at best a 40% to 50% overall survival. (Clarke et al., 2005) (Konkin et al.,2006) In addition, axillary node dissection has been considered an important step in patient management by determining the type and extent of systemic therapy necessary. Despite these roles, axillary node dissection can significantly compromise patients' quality of life by the occurrence of lymphedema, pain, restriction of shoulder movement, or anesthesia. (Langer et al., 2007) The emergence of SNB has permitted reliable identification of axillary nodal metastases in a clinically negative axilla, therefore sparing 60% to 75% of patients the excess morbidity of ALND. Still, 25% to 40% of patients require completion ALND following positive SNB. (Kim et al., 2006) Axillary irradiation is a rational alternative to ALND. In a clinically negative axilla, irradiation achieves comparable local tumor control with less morbidity. In addition, there is now less reliance on the number of axillary lymph nodes with metastases as the primary indicator for systemic therapy. Other factors have emerged that may indicate the need for and the type of systemic therapy to be delivered including HER 2 neu overexpression, other gene expression, negative hormone receptors, and so forth. The combination of sentinel node biopsy to detect axillary metastases, other prognosticators as indicators for systemic therapy, and axillary irradiation for regional tumor control potentially fulfills the three primary goals of ALND. (Jay et al., 2010) Several studies have demonstrated that the axillary reverse mapping nodes are involved with metastatic foci in some patients with extensive axillary lymph node metastasis. Therefore, patients with suspected extensive nodal disease at clinical examination, ultrasonography of the axilla, or intraoperative pathologic assessment should not be candidates for preservation of axillary reverse mapping nodes and lymphatics. On the other hand, the SLN draining the breast is the same node as the axillary reverse mapping node draining the upper extremity in some patients, It is impossible to preserve converged sentinel lymph node – axillary reverse mapping node, although the excision of one converged node does not always translate into lymphedema, because multiple lymphatic channels drain the arm. Thus, there is no reliable separation of arm and breast lymphatic pathways, because there are lymphatic interconnections between lymph nodes draining the upper extremity and nodes draining the breast. However, it has been suggested that patients with clinically uninvolved nodes might derive the most benefit from the axillary reverse mapping procedure. (Jay et al., 2010)