Chapter 79: Management of the Pathologically Positive Axilla

INTRODUCTION

A generally accepted tenet of management of solid tumor malignancies—including adenocarcinoma of the breast—is that most bulky/clinically evident sites of disease are best managed by surgical resection, with radiation treatment reserved for microscopic, clinically occult foci of soft tissue disease. The goal of systemic therapy is to eradicate distant organ disease. Clearly, however, there will be overlap in the results achieved by these modalities of cancer care, and these effects can influence the extent of necessary surgery as well as the sequence of delivering these components of cancer care. For example, a patient that initially presents with bulky axillary lymph nodes will likely require an anatomically defined level I/II axillary lymph node dissection, and this surgery may be performed as initial primary treatment as long as there is no evidence of unresectable disease that would place the axillary neurovascular structures at risk for intraoperative damage. However, these patients will routinely require chemotherapy because the axillary disease reflects an increased likelihood of harboring distant organ micrometastatic disease, even in the presence of negative body imaging. These cases, therefore, become very strong candidates for receiving preoperative/neoadjuvant chemotherapy, which can also downstage the extent of the axillary disease. Whether or not axillary downstaging by neoadjuvant chemotherapy can diminish the extent of axillary surgery, and make the patient a candidate for axillary sentinel lymph node biopsy alone is an ongoing subject of debate in the oncology literature. At the other end of the spectrum, patients with low-volume disease in the axilla that is detected by a staging procedure (such as sentinel lymph node biopsy or axillary ultrasound and sono-guided needle biopsy) will typically receive adjuvant chemotherapy therapy, and the locoregional effects of systemic therapy coupled with radiation may be adequate in replacing the need for a completion axillary lymph node dissection in selected cases.

In light of the various multimodality treatment options that are available, it can therefore be useful to discuss management of breast cancer patients with pathologically proven axillary metastatic disease by categorizing their status and treatment plan as follows:

1. Cases of axillary metastases presenting as palpable, clinically suspicious disease

   1. Associated with a locally advanced primary breast cancer

   2. Associated with an early-stage breast cancer

   3. Associated with an occult primary tumor in the breast

2. Cases of axillary metastases identified by sentinel lymph node biopsy

   1. In patients undergoing primary surgery for early-stage breast cancer

   2. In patients undergoing axillary staging prior to receiving neoadjuvant chemotherapy

3. Cases of axillary metastases identified by axillary ultrasound and sono-guided fine needle aspiration (FNA) or core needle biopsy of morphologically abnormal-appearing but nonpalpable lymph nodes

   1. In patients undergoing primary surgery for early-stage/resectable breast cancer

   2. In patients undergoing axillary staging prior to receiving neoadjuvant chemotherapy

In distinguishing which of the three umbrella categories is appropriate for an individual patient, confirmation of nodal metastatic involvement is generally necessary. As demonstrated by the landmark NSABP B-04 trial,¹ clinical examination is notoriously inaccurate in assessing ...