Objective. Optimal management of the contralateral groin in patients with early-stage vulvar squamous cell carcinoma (VSCC) and a metastatic unilateral inguinal sentinel lymph node (SN) is unclear.... Show moreObjective. Optimal management of the contralateral groin in patients with early-stage vulvar squamous cell carcinoma (VSCC) and a metastatic unilateral inguinal sentinel lymph node (SN) is unclear. We analyzed patients who participated in GROINSS-V I or II to determine whether treatment of the contralateral groin can safely be omitted in patients with a unilateral metastatic SN.Methods. We selected the patients with a unilateral metastatic SN from the GROINSS-V I and II databases. We determined the incidence of contralateral additional non-SN metastases in patients with unilateral SN-metastasis who underwent bilateral inguinofemoral lymphadenectomy (IFL). In those who underwent only ipsilateral groin treatment or no further treatment, we determined the incidence of contralateral groin recurrences during follow-up.Results. Of 1912 patients with early-stage VSCC, 366 had a unilateral metastatic SN. Subsequently, 244 had an IFL or no treatment of the contralateral groin. In seven patients (7/244; 2.9% [95% CI: 1.4%-5.8%]) disease was di-agnosed in the contralateral groin: five had contralateral non-SN metastasis at IFL and two developed an isolated contralateral groin recurrence after no further treatment. Five of them had a primary tumor >= 30 mm. Bilateral ra-diotherapy was administered in 122 patients, of whom one (1/122; 0.8% [95% CI: 0.1%-4.5%]) had a contralateral groin recurrence.Conclusion. The risk of contralateral lymph node metastases in patients with early-stage VSCC and a unilateral metastatic SN is low. It appears safe to limit groin treatment to unilateral IFL or inguinofemoral radiotherapy in these cases.(c) 2022 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY license (http:// creativecommons.org/licenses/by/4.0/). Show less
