Breast cancer is the most common cancer of women. Surgery for early breast cancer includes axillary lymph nodes staging. Axillary surgery may lead to intractable complications like permanent arm swelling. Axillary sentinel lymph node biopsy (SLNB) has been introduced to minimize the incidence of these complications. Several methods are routinely used for identification of the sentinel node during operation. Some of these methods necessitate facilities that are not universally available; specially in countries with limited resources. In its simplest form, SLNB using the methylene blue dye technique has an identification rate of 88-94%. If the sentinel node can not be identified, full axillary dissection may be required and the risk of arm swelling is increased. The objective of this study is to maximize the identification rate of the sentinel node thus avoiding the need for extensive axillary surgery. The investigators assumed that preoperative tattooing of the suspicious lymph node during ultrasonographical imaging may help the surgeon in localizing the sentinel lymph node. In this study, the sonographer will perform preoperative tattooing of the suspicious node. The surgeon will perform SLNB by the methylene blue dye. The sensitivity of ultrasonographical tattooing relative to SLNB will be calculated. The study will determine if the tattooing technique may localize additional nodes that are missed by the methylene blue.

Introduction Axillary nodal staging is an integral part of breast cancer management. Sentinel lymph node biopsy (SLNB) has become a standard of care in patients with clinically negative axillae. Various methods have been investigated to decrease the false negative rate of SLNB. Ultrasonography is an established tool for preoperative axillary staging. The diagnostic accuracy of B-mode ultrasonographic criteria and of US-guided FNAC (Fine Needle Aspiration Cytology) has been described in the literature and its role in preoperative axillary staging has been emphasized.

Ultrasonographic aspiration of suspicious axillary nodes are widely used to identify axillary metastases and obviate the need for SLNB. Previous studies retrospectively examined the concordance of ultrasonographic identification of suspicious lymph nodes with subsequent SLNB results. However, ultrasonographic axillary staging have not been prospectively compared to SLNB. In addition, concomitant ultrasonographic and SLNB are thought to increase the overall accuracy of axillary staging.

In this study, the investigators will perform preoperative ultrasonographic axillary evaluation and tattooing of suspicious lymph nodes followed by SLNB with methylene blue technique. Head-to-head and node-to-node comparison of ultrasonographic and surgical staging will be conducted.

Specific aims

1. Determination of the diagnostic accuracy of preoperative ultrasonic guided tattooing of suspicious axillary lymph nodes.
2. Determination of node-to-node concordance of ultrasonographic tattooing relative to blue dye SLNB.

Inclusion Criteria:

• Biopsy-proven invasive breast adenocarcinoma.
• Clinically non palpable axillary lymph nodes.
• T0-3, N0, M0
• Scheduled for definitive surgery.

Exclusion Criteria:

• Patient unwilling to participate.
• Contraindication to methylene blue technique: hypersensitivity, pregnancy.
• T4 primary tumor.
• Previous axillary surgery.