Evaluation of sentinel lymph nodes in breast cancer.

Sentinel lymph node biopsy is an accurate method for the detection of axillary metastases in cases of breast carcinoma and is of value as a replacement for axillary dissection. There is variation, however, in the methods and protocols used for the histopathological evaluation of sentinel lymph nodes, standardisation of which will be required if results of sentinel lymph node analysis are to be used to stratify patients into prognostic groups. The significance of micrometastases, isolated tumour cells (ITCs) and the value of immunohistochemistry are also matters for further definition. In this Expert Opinion we present reviews from two authors, providing American and European perspectives on the approach to sentinel lymph node evaluation.