Preoperative and Intraoperative Quantification of Axillary Tumoral Load to Reduce the Need of Axillary Lymph Node Dissection in Breast Cancer Patients With Positive Lymph-nodes at Diagnosis

At present, patients diagnosed of a breast cancer with infiltration of the axillary lymph-nodes are submitted to axillary lymph-node dissection (ALND). The sentinel node (SN) technique is not indicated when a lymph-node biopsy or cytology is positive, nor when the surgical treatment is upfront neither when a neoadjuvant systemic therapy is indicated. The reason for not performing SN is that patients diagnosed of an infiltrated axilla though ultrasound-guided biopsy or cytology tend to have a higher tumoral load than those diagnosed after a sentinel biopsy. Furthermore, even if these patients are submitted to a neoadjuvant systemic treatment and the axillary clinical exploration is negative after the treatment, different studies showed that the SN false negative rate is unacceptably high.

Despite these facts, a high proportion of patients with a positive axilla at diagnosis and submitted to level I and II axillary lymph node dissection show few lymph nodes infiltrated in the pathological study, frequently four or less neoplastic nodes. New methods of detecting these patients with limited infiltrated nodes should be developed and new approaches to axillary surgery (i.e., partial resection) should be offered.

To date, the only information expected to get after an axillary imaging is performed is if the axilla is infiltrated or not. No information about the tumoral load is demanded. In the other hand, level I and II ALND is performed according to established anatomic limits, without selecting the nodes to be excised neither identifying the ones infiltrated for a directed excision.

The aim of the study is to evaluate the ability of a specified and reproducible imaging protocol for distinguishing patients with a high axillary tumoral load from the ones with a low tumoral load. At the same time, as the initial nodes receiving lymph drainage should be the ones commonly affected, identifying these nodes injecting diluted methylene blue in the retroareolar parenchyma and studying their tumoral load could help selecting patients with high from those with low axillary tumoral load.

Evaluation of both steps (that is, first the imaging protocol followed by the methylene blue protocol), could eventually help to distinguish which patients should be submitted to a classical level I and II ALND and which ones can be spared from excising the lymph nodes not stained by the methylene blue.