Sentinel node biopsy in vulvar cancer: Implications for staging

•Sentinel node biopsy is safe in well-selected patients with early-stage vulvar cancer.•Sentinel node biopsy enables pathologic ultrastaging of the first draining lymph node.•Chances of survival decrease with increasing size of sentinel node metastasis.•Staging of vulvar cancer was changed in 2009, including size of lymph node metastases.•Clinical implications of size of metastases are not clear yet.

In 2008, the first Groningen International Study on Sentinel nodes in Vulvar cancer (GROINSS-V) showed that omission of inguinofemoral lymphadenectomy is safe in patients with early-stage vulvar cancer and a negative sentinel node and it simultaneously decreases treatment-related morbidity. An important part of the sentinel node procedure is pathologic ultrastaging of the removed sentinel nodes. Subsequently, since the introduction of this procedure in the standard care of patients with early-stage vulvar cancer, more and smaller inguinofemoral lymph node metastases have been diagnosed. The clinical consequences of these micrometastases are not clear yet. With increasing size of the sentinel node metastasis, chances of non-sentinel node metastases increase and those of survival decrease. The size of lymph node metastases is included in the latest staging system for vulvar cancer, however at this moment without clinical implications. Furthermore, a separate category for micrometastases is not incorporated yet. More research is needed to determine the clinical consequences of the size of (sentinel) lymph node metastases.