The Roles of Ultrasonography in the Management of Axillary Node Metastases in Breast Cancer

Review Article

Austin J Cancer Clin Res 2015;2(7): 1058.

The Roles of Ultrasonography in the Management of Axillary Node Metastases in Breast Cancer

Rosso KJ¹, Ko Un Park¹, Shah R¹, Rubino G² and Nathanson SD¹*

¹Department of Surgery, Henry Ford Hospital and Wayne State University School of Medicine, USA

²Wayne State University School of Medicine, USA

*Corresponding author: S David Nathanson, Department of Surgery, Henry Ford Health System, Wayne State University School of Medicine, 2799 W, Grand Boulevard, Detroit, MI 48202, USA

Received: June 22, 2015; Accepted: August 05, 2015; Published: August 08, 2015


In patients with early stage breast cancer, surgical management of the axilla has become less invasive. Multiple randomized control trials have demonstrated that in patients with minimal axillary nodal disease, complete axillary lymph node dissection does not offer a survival benefit when compared to sentinel lymph node biopsy alone. Ultrasonography of the axilla and ultrasound guided biopsy of suspicious lymph nodes has become a highly specific test to identify locoregional disease. Nodal metastasis detected by ultrasound guided lymph node biopsy has allowed patients to be treated as “lymph node positive” or N1, receive neoadjuvant chemotherapy and undergo a subsequent definitive axillary operation. In those patients who achieve a pathologic complete response after neoadjuvant chemotherapy, however, removal of axillary nodes that are free of residual cancer may be of no benefit. Targeted axillary dissection is a novel technique that allows limited, image guided removal of the previously biopsied axillary nodes and the sentinel lymph node during definitive axillary dissection following neoadjuvant chemotherapy. This practice relies on the specificity of ultrasound guided axillary lymph node biopsy to detect disease as well as the placement of markers that label the biopsied node. Contemporary research that utilizes ultrasound to differentiate between patients with minimal axillary nodal metastasis from those with extensive axillary nodal disease will contribute substantially to the less invasive surgical management of the axilla.

Keywords: Axillary node; Breast cancer; AUS


The sentinel lymph node (SLN) is the first node (or nodes) to receive tumor cells traveling from the primary tumor to the locoregional nodal basin. The surgical sentinel lymph node biopsy (SLNB) relies on orderly lymphatics from the breast to the axilla and the combined use of blue dye and radiolabeled colloid tracers allows for its highly accurate localization. Since its inception and subsequent application, the SLNB has become the validated gold standard to stage the axilla. Clinically, lymph node status remains one of the most important prognostic factors in breast cancer and guides treatment algorithms.

Axillary ultrasound (AUS) with ultrasound guided lymph node biopsy (either by fine needle aspiration or core needle) can identify most patients with extensive axillary nodal disease burden with specificity approaching 100%. Sonographic characteristics suspicious for metastasis in the lymph node include cortical thickening, changes in shape and size and absence of the fatty hilum but the morphology that defines presence of metastasis or indication for ultrasound guided lymph node biopsy (USLNB) is not standardized.

Prior to the Z0011 trial [1] demonstrating that complete axillary dissection offered no survival benefit in patients with limited axillary disease, AUS was used for preoperative locoregional staging. A positive AUS and USLNB allowed the patient to undergo neoadjuvant chemotherapy and one definitive axillary surgery by avoiding the SLNB altogether.

Following Z0011 and the subsequent randomized trials like AMAROS [2] echoing its results, management of the axilla has become less invasive and the role of AUS and USLNB is being redefined. Some centers abandoned preoperative ultrasonographic axillary staging in the clinically negative axilla, others rely on a negative preoperative AUS with USLNB to determine if the patient is indeed a candidate for surgical management by Z0011 criteria, while other institutions consider a positive AUS and USLNB to be N1 disease and treated as such. The clinical application of AUS and USLNB in the post-Z0011 era is highly variable. The National Comprehensive Cancer Network guidelines do not advocate for routine axillary ultrasonography in patients with clinically negative axilla (cN0) [3]. New promising randomized trials like the SOUND study [4] are attempting to identify the most efficient and beneficial utilization of this imaging modality in the management of the axilla breast cancer. These contemporary studies aim to investigate disease free and overall survival in patients with early breast cancer and negative AUS that are randomized to SLNB or no further axillary staging. This article reviews the abnormal morphology of a suspicious lymph node, sensitivity, specificity, predictive values and common indications for AUS and USLNB, techniques to mark the biopsied node, utilization of AUS USLNB following neoadjuvant chemotherapy, and lastly, some promising studies that will help further define and standardized its use.

Identifying a suspicious lymph node by ultrasonography

Ultrasound examination should include the total axilla extending to the anatomic borders from the level of the fourth rib inferiorly to the costoclavicular ligament and axillary vein superiorly, and from the pectoralis muscles anteriorly to the subscapularis and latissimus dorsi muscles posteriorly [5]. There is a high concordance rate of finding the true SLN when the ultrasound is focused in the same anatomic area as used by surgeons during open SLNB [5]. Most SLNs are found intraoperatively close to the lowest axillary hair follicle [5] and more than 80% of sentinel nodes by ultrasound represent the lowest node in the axilla [6].

Distinctions between normal appearing nodes, solitary sonographically abnormal appearing nodes or multiple abnormal nodes should be documented [7], as should the location of the abnormal node or nodes within the axilla. A normal appearing lymph node is characterized by having an elliptical shape, a thin, even hypoechoic cortex measuring <3mm, and a hyperechoic hilum with blood vessels entering the hilum [5,8]. Common sonographic findings of a suspicious or abnormal lymph node include a thickened, lobulated cortex >3mm, loss or effacement of the fatty hilum, and loss of normal lymph node architecture [5,6,9-20] (Table 1), but these morphological characteristics have yet to be standardized. Such variations in the criteria that define an abnormal node and thus the indications for biopsy affect the sensitivity and specificity of AUS and USLNB [5,7,8,12-15,17-20] (Table 2).