Update on the Sentinel Node Procedure in Vulvar Cancer

Early-stage vulvar cancer is managed by a local excision of the primary tumor and, if indicated, a sentinel node (SN) biopsy to assess the need for further groin treatment. With the SN procedure, many patients can be treated less radically and will experience less complications and morbidity compared with an inguinofemoral lymphadenectomy (IFL). Still, the SN procedure can be further optimized. Different tracers for detecting the SN are being investigated, aiming to optimize detection rates and decrease the burden of the procedure and short-term complications. Until now, no standardized protocols exist for the pathologic workup of the SN, possibly leading to discrepancies in detection of metastases between institutes using different methods. New techniques, such as one-step nucleic amplification, seem to have potential in accurately detecting metastases in other cancers, but have not yet been investigated in vulvar squamous cell carcinoma (VSCC). Furthermore, several studies have investigated the possibility to broaden the indications for the SN procedure, such as its use in recurrent disease, larger tumors, or multifocal tumors. Although these studies show encouraging results, cohorts are small and further studies are needed. Prospective studies are currently investigating these subgroups. Lastly, several studies investigated optimization of groin treatment of patients with a metastatic SN. Inguinofemoral radiotherapy is a good alternative to IFL in patients with micrometastases in the SN, with comparable efficacy and less treatment-related morbidity. Reduction of the radicality of groin treatment is also possible in other ways, such as omitting contralateral IFL in patients with lateralized tumors and a unilateral metastatic SN. In conclusion, the SN procedure is an established procedure in early-stage VSCC, although optimization of the technique, pathologic workup, indications, and treatment in the setting of metastatic disease are the subject of ongoing research.