Sentinel lymph node biopsy in breast cancer surgery

Abstract

Axillary lymph node status is one of the most reliable prognostic factors of long-term survival in breast cancer surgery. Metastatic involvement of the axillary lymph nodes is also crucial in the decision making of potentially useful adjuvant treatment. Until the last decade, Axillary Lymph Nodes Dissection (ALND) was performed in order to obtain the regional lymphatic system staging. In case of non-metastatic spread, that kind of surgery was limited only to this purpose; no further oncological benefits were obtained and the patients were exposed to several comorbidities affecting this type of surgery. Complications after ALND are reported in 15-30% of cases. They are well known and range from early bleeding, infection, symptomatic nerve damage, and longstanding limb lymph-edema with an incredible impairment of the quality of life.
The Sentinel Lymph Node (SLN) theory holds that the SLNs are the first nodes draining lymph from an anatomic region (i.e. the breast) where metastatic disease will most likely to be found. If that node is found to be cancer free, the entire lymphatic system is likely to be cancer free; if it is metastatic, there is an elevated chance of finding more metastatic nodes. Thanks to the application of this hypothesis, several patients over the last 10-15 years have avoided unnecessary major demolitive surgery. To obtain accurate evaluation of the SLN a multidisciplinary dedicated team is necessary. This procedure has been internationally validated and the false negative rate is nowadays less than 5% when performed by expert hands. Dedicated breast surgeons working in a high-volume centres are necessary to reach satisfactory confidence in performing this very specialised procedure in order to obtain an accurate staging. The number of women presenting to the breast oncology units is continuously increasing and the implementation of screening programs has been crucial in detecting numerous patients (more than 75%) with early disease and non-metastatic axillary lymph nodes. The practice of the SLN is clearly able to offer those patients an accurate staging with low comorbidities, preserving their quality of life.