Sentinel Lymph Node Biopsy in the Management of Vulvar Carcinoma: An Evidence-Based Insight

Lymph node metastasis has been shown to represent the most significant prognostic factor in vulvar carcinoma. Because only 25% to 35% of patients with early stage disease have lymph node metastases, a significant 65% to 75% possibly do not benefit from elective inguinofemoral lymphadenectomy considering the related morbidities of wound infection, breakdown, and lower limb lymphedema. This review article aims to present and summarize the evidence available with regard to sentinel lymph node (SLN)-guided management of vulvar carcinoma.

A literature search was performed in MEDLINE resources using the subject headings "vulvar neoplasms," "sentinel lymph node," "sentinel lymph node biopsy," and "lymphatic metastasis." This search returned 886 articles that were published through January 2017. Prospective studies investigating sentinel node identification techniques and their impact on vulvar cancer management and prognosis were considered. Case reports were excluded from the review.

Technetium-99-m-labeled nanocolloid with or without blue dye and more recently indocyanine green fluorescence have been the main techniques used for SLN identification in vulvar carcinoma. Radioisotope and near-infrared techniques have been shown to be superior to blue dye particularly with midline lesions that drain bilaterally or that drain directly to a deep pelvic node. Patients with a small unifocal primary tumor (<4 cm) and no obvious preoperative metastasis have been shown to have low groin recurrence rates and excellent disease-specific survival rates with minimal treatment-related morbidity when undergoing SLN biopsy-guided management.

Sentinel lymph node biopsy-guided management seems to be safe when restricted to International Federation of Gynecology and Obstetrics IB to II cases where tumors are unifocal, less than 4 cm in size, and when there is no evidence of lymph node metastasis on clinical/radiological assessment. This reduces operative morbidity in this cohort of patients.