Feasibility and recurrence risk of sentinel lymph node biopsy in large vulvar tumors (≥4 cm)

To evaluate the feasibility of sentinel lymph node biopsy in vulvar tumors ≥4 cm and compare groin recurrence rates to tumors <4 cm.

This retrospective single-center cohort study included patients with invasive vulvar squamous cell carcinoma between 2008 and 2024. All patients underwent primary surgical excision with planned sentinel lymph node biopsy. Sentinel lymph node procedures in tumors ≥4 cm were performed at the surgeon's discretion. Patients were stratified by tumor size (<4 cm vs ≥4 cm). Analysis included descriptive statistics, Kaplan-Meier curves for groin recurrence-free survival, and multivariate analysis using a Cox proportional hazards model.

Among 298 patients (490 groins), 233 had tumors <4 cm and 65 had tumors ≥4 cm. A sentinel lymph node was identified in 93.9% of tumors ≥4 cm. Larger tumors were associated with older age (p = .04), deeper depth of invasion (p < .0001), higher grade (p < .0001), and lymphovascular space invasion (p = .0002). Tumors ≥4 cm had significantly more positive sentinel lymph nodes (p = .04), extracapsular extension (p = .01), and groin node dissections (p = .048). Among 339 groins with negative sentinel lymph node (275 in tumors <4 cm and 64 in tumors ≥4 cm), isolated groin recurrences occurred in 15.6% of larger tumors and 5.1% of smaller tumors (p = .0002). The 3-year groin recurrence-free survival was higher for tumors <4cm (92.5% vs 73.3%, p=.0097). Multivariate analysis revealed that tumor size ≥4 cm was associated with an increased risk of groin recurrence (hazard ratio 1.17, 95% confidence interval 1.05 to 1.29, p = .003).

Sentinel lymph node identification in tumors ≥4 cm was feasible but associated with worse groin recurrence-free survival despite negative sentinel lymph nodes. For patients with tumors ≥4 cm, cautious patient selection is important to balance morbidity and prognostic information.