TY - JOUR T1 - 2022-RA-690-ESGO Unilateral inguinofemoral lymphadenectomy in patients with early-stage vulvar squamous cell carcinoma and a unilateral metastatic sentinel lymph node is safe JF - International Journal of Gynecologic Cancer JO - Int J Gynecol Cancer SP - A430 LP - A430 DO - 10.1136/ijgc-2022-ESGO.925 VL - 32 IS - Suppl 2 AU - Willemijn L van der Kolk AU - Ate GJ van der Zee AU - Brian Slomovitz AU - Peter JW Baldwin AU - Helena C van Doorn AU - Joanne A de Hullu AU - Jacobus van der Velden AU - Katja N Gaarenstroom AU - Brigitte FM Slangen AU - Preben Kjølhede AU - Mats Brännström AU - Ignace Vergrote AU - Cathrine M Holland AU - Robert Coleman AU - Eleonora BL van Dorst AU - Willemien J van Driel AU - David Nunns AU - Martin Widschwendter AU - David Nugent AU - Paul A DiSilvestro AU - Robert S Mannel AU - Ming Y Tjiong AU - Dorry Boll AU - David Cibula AU - Al Covens AU - Diane Provencher AU - Ingo B Runnebaum AU - Bradley J Monk AU - Vanna Zanagnolo AU - Karl Tamussino AU - Maaike HM Oonk AU - GROINSS-V I and II participants Y1 - 2022/10/01 UR - http://ijgc.bmj.com/content/32/Suppl_2/A430.1.abstract N2 - Introduction/Background 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 GROningen INternational Study on Sentinel nodes in Vulvar cancer (GROINSS-V) I or II to determine whether treatment of the contralateral groin can safely be omitted in patients with a unilateral metastatic SN.Methodology 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 eight patients (8/244; 3.3% [95% CI: 1.7%-6.3%]) disease was diagnosed in the contralateral groin: six had contralateral non-SN metastasis at IFL and two developed an isolated contralateral groin recurrence after nu further treatment. Six of them had a primary tumor ≥30 mm. Bilateral radiotherapy 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, particularly if the primary tumor is <30 mm. ER -