Axillary Reverse Mapping

V. Suzanne Klimberg

Introduction

The status of the regional lymph node(s) is a key prognostic variable, and therapeutic decisions are based on the presence or absence of breast cancer cells metastatic to the regional axillary lymph node(s). The basic technique of axillary lymph node dissection (ALND) has changed little over several decades; the principal features are that of an anatomical dissection. However, individual modifications of the ALND technique has resulted in the reported variations in the one of the most commonly reported complications of axillary surgery, lymphedema. Depending on the definition of lymphedema, the incidence has been reported as high as 50% dependent upon the radicality of the procedure and the necessity for adjuvant radiation. Sentinel lymph node biopsy (SLNB) was introduced a little over a decade ago as an initial procedure to determine the accurate presence of regional metastases and, thus, the need for the more extensive ALND. Therefore, allowing 70% to 80% of patients to forgo ALND. From its inception, SLNB has been assumed to be and appears to be less morbid in multiple small trials comparing the two procedures. The most recent studies of lymphedema after ALND report lymphedema in 7% to 77% of patients. Lymphedema after SLNB has been reported from 0% to 13%. National Surgical Adjuvant Breast and Bowel Project (NSABP) B-32 is a large randomized cooperative group trial that will be able to answer the question of whether there is a survival difference between the two procedures in patients with negative axillary lymph nodes and the extent of the difference in lymphedema between the two procedures. We have recently introduced axillary reverse mapping (ARM) as an added procedure to either SLNB or ALND to identify and protect lymphatics draining the arm in order to prevent the sequelae of lymphedema.

Indications/Contraindications

We have recently described the variations in lymphatics draining the arm within the axilla. These variations in arm lymphatic drainage put the arm lymphatics at risk for disruption during SLNB and/or ALND. Therefore, mapping the drainage of the arm during SLNB or ALND would be indicated to decrease the likelihood of inadvertent
disruption of the lymphatics. Axillary reverse mapping is a method of separating nodes draining the breast from those draining the arm in order to preserve arm lymphatics and prevent lymphedema.

Axillary reverse mapping may be used with any size lesion and when lymph node involvement is present and after neoadjuvant therapy. When previous axillary surgery has been performed such as SLNB without ARM, lymphatics may have already been disrupted and the value of ARM added to ALND in this scenario may be limited.

In patients with matted nodes, the drainage of the breast can back up into the lymphatics draining the arm, and the safety of ARM is unknown. In addition, matted breast nodes can entrap low-lying ARM lymphatics, making it impossible to preserve them.

Preoperative Planning

Materials

Radioactive Materials

Any of the various materials previously established for the localization and SLNB may be used including but not exclusively technetium Tc 99m sulfur colloid (filtered or unfiltered) or technetium Tc 99m albumin. (See Chapter 10.)

Blue Dye

Five milliliters of 1% isosulfan blue dye (BD) is used for injection into the arm. When performing bilateral ARM procedures, this dose may be used for each side, or a single dose may be diluted with 5 ml of saline and divided for bilateral injection.

The Gamma Detector

The type of instrument used for detection of the sentinel lymph node (SLN) may be any of the marketed Food and Drug Administration (FDA)–approved devices with a collimated beam. The surgeon has the discretion of selecting a gamma detector that best serves his or her needs.

Radiation Safety

The handling, administration, and disposal of radioactive wastes should be performed in accordance with institutional policy. All radioactive specimens will be labeled with a sticker indicating the presence of radioactive materials. In all cases, strict precautions should be maintained according to radiation safety guidelines of handling open containers of radiopharmaceuticals. All materials used for injection (syringe, gloves, gauze) should be handled and disposed of in an appropriate container.

Relevant Anatomy

The anatomy of the lymphatic system draining the breast as it lies is the axilla is shown in Figure 13.1. In general the axillary triangle (level I axillary lymph nodes in which the lymphatics of the axilla sit is bordered by the serratus anterior and the pectoralis minor medially, the latissimus dorsi laterally, the axillary vein superiorly, and the teres major posteriorly (Fig. 13.2). Level II lymphatics are posterior to and in front of (Rotter’s nodes) the pectoralis minor. Level III lymphatics are medial to the pectoralis minor. Recently, we described a method (ARM) that can demarcate the axillary lymph nodes draining the breast from those draining the arm within the axilla and the variations that have been identified (Fig. 13.3).

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