Current management of sentinel lymph nodes: perspectives from pathology

Sentinel Lymph Node Biopsy or Detection of Micrometastasis in Bone Marrow: Which Might Be an Alternative to Axillary Lymph Node Dissection in Breast Cancer Patients?

Axillary lymph node status has limited prognostic significance in breast cancer patients and much improvement can be made. Sentinel lymph node biopsy is emerging as an alternative to axillary lymph node dissection for staging, but its prognostic relevance is still uncertain. Detection of micrometastases in sentinel nodes and bone marrow may provide more information, but the clinical significance still needs to be confirmed by ongoing large trials. In this review, we focus on the possibility of sentinel lymph node biopsy or detection of bone marrow micrometastasis replacing traditional axillary lymph node dissection.

Pathologic analysis of sentinel lymph nodes in melanoma patients: Current and future trends

Sentinel lymph node dissection (SLND) has become the standard of care for the staging of clinically-node negative melanomas and breast cancers. A large literature documents the efficacy of SLND in the staging of melanoma and breast cancer. The SLND has lower associated patient morbidity in comparison to elective node dissections that remove the closest regional-draining node group. SLND has improved accuracy over traditional regional node dissection for the staging of melanoma. Currently, several multicenter trials are evaluating the prognostic significance of melanoma micrometastases in SLN detected by immunohistochemical and molecular methods. Pending trial outcome analysis, SLND has no proven effect on mortality. However, given the current oncologic emphasis on detection and removal of nodal tumor metastases, the technique has an important role in minimizing the invasiveness of tumor staging for melanoma and breast cancer. As long as lymph node metastases are used for staging solid malignancies, surgical pathologists are likely to encounter SLN excisional biopsies as a part of their routine practice.

The use of sentinel lymph nodes in gynaecological malignancies

PURPOSE OF REVIEW

Lymphatic mapping and sentinel node biopsy represent one of the most revolutionary advances in oncological surgery in recent years. In this review, the current state of sentinel node detection in gynaecological cancers and its use in vulvar and cervical cancer are assessed.

RECENT FINDINGS

Since the recent clinical application of sentinel node biopsy for melanomas and breast cancer, there has been extensive research on the implementation of this technique to most solid neoplasias. Studies on the feasibility of sentinel node biopsy in vulvar cancer have shown that the status of the sentinel node is an accurate predictor of the status of inguinal nodes. The clinical implementation of the procedure requires validation and is under investigation. In the last two years, several pilot studies on the feasibility of lymphatic mapping/sentinel node biopsy in cervical cancer have yielded promising results. There is minimal experience of its use in endometrial cancer. Detailed pathological study of a sentinel node biopsy with ultrastaging and immunohistochemical or polymerase chain reaction analyses can identify lymph node micrometastasis that conventional methods would identify as negative for metastatic disease. The best histopathological procedure for sentinel node biopsy, the clinical significance of micrometastases, and the appropriate management of such micrometastases are currently under investigation.

SUMMARY

Sentinel node biopsy is one of the main research interests in gynaecological oncological surgery. At present there are not enough data to permit modification of current treatment protocols. Large and multi-institutional trials are required in order to define the implementation of sentinel node biopsy in clinical practice with the objective of achieving safer and more conservative surgery.