Sentinel lymph node biopsy in breast cancer patients: the medical oncology perspective

Recent data indicates that the sentinel lymph node biopsy (SLNB) is a possible alternative to axillary lymph node dissection (ALND) in early breast cancer patients, with minimal risk of complications. From the medical oncologist's point of view, the impact of SLNB on the management of patients should consider if SLNB is useful to choose adjuvant treatment, if it is adequate to provide local control, and what is the significance of lymph node micrometastases on treatment and staging. Lymph node involvement has always been recognised as the most important prognostic factor in early-stage breast cancer, even if many other parameters have been evaluated in recent years. However, the lack of knowledge of nodal status in patients with false-negative SLNB seems to result in an undertreatment in a very low percentage of patients. Adjuvant chemotherapy and hormonal therapy with tamoxifen are associated with an absolute reduction of the risk of recurrence and death both in node-positive and in node-negative patients, then if patients are treated with modern adjuvant systemic therapy, any effect associated with false negative SLN should be minimised. The impact of axillary treatment on survival is still controversial, but in recent times axillary lymph node positivity is considered as an indicator for high risk of systemic diffusion of the disease rather than a possible origin of systemic metastases. The significance of occult sentinel lymph node metastases detected by immunohistochemistry (IHC) or molecular biology on prognosis is still uncertain. The new version of the staging system of breast cancer has recognised the need for a standard diagnostic approach and of a nomenclature system which also takes SLNB into account.