Localization of sentinel lymph node in breast cancer. A prospective study

Sentinel Lymph Node Biopsy (SLNB) is the standard of care for staging axillary lymph nodes in women with breast cancer and clinically negative nodes. It is associated with reduced arm morbidity, moderated or severe lymphoedema, and a better quality of life in comparison with standard axillary treatment. Unfortunately, skip metastases makes all minimally invasive approaches, such as axillary sampling, unreliable. The aim of the present clinical prospective study is to evaluate the position of SLN in an important number of cases and establish the real incidence of skip metastases in clinically node-negative patients.

A cohort of 898 female patients with breast carcinoma was considered, from 2001 to 2008. Once SLN was localized, by means of radio-colloid or blue dye staining, and isolated, a biopsy was performed. Only those positive for metastases were submitted to axillary dissection.

Only in nine cases a SLN was not isolated. We had 819 cases of first level SLN (group A) and 69 cases of second level SLN (group B). Considering all of 889 cases, SLN was localized in the second level in 69 patients (7.8%); but if we consider metastatic SLN alone (340 cases), it was in the second level in 23 subjects (6.8%). In total, we had a positive second level SLN in 2.3% of cases (23/889).

Second level SLN could be considered only an anomalous lymphatic axillary drainage and it does not linked to particular histological variants of the primitive tumour. In our study, skip metastases were recognized in only 2.6% of cases, therefore, whenever a SLN is not isolated for any reason, the first level sampling represent a viable operative choice.