@article {KolkA430, author = {Willemijn L van der Kolk and Ate GJ van der Zee and Brian Slomovitz and Peter JW Baldwin and Helena C van Doorn and Joanne A de Hullu and Jacobus van der Velden and Katja N Gaarenstroom and Brigitte FM Slangen and Preben Kj{\o}lhede and Mats Br{\"a}nnstr{\"o}m and Ignace Vergrote and Cathrine M Holland and Robert Coleman and Eleonora BL van Dorst and Willemien J van Driel and David Nunns and Martin Widschwendter and David Nugent and Paul A DiSilvestro and Robert S Mannel and Ming Y Tjiong and Dorry Boll and David Cibula and Al Covens and Diane Provencher and Ingo B Runnebaum and Bradley J Monk and Vanna Zanagnolo and Karl Tamussino and Maaike HM Oonk and GROINSS-V I and II participants}, title = {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}, volume = {32}, number = {Suppl 2}, pages = {A430--A430}, year = {2022}, doi = {10.1136/ijgc-2022-ESGO.925}, publisher = {BMJ Specialist Journals}, abstract = {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.}, issn = {1048-891X}, URL = {https://ijgc.bmj.com/content/32/Suppl_2/A430.1}, eprint = {https://ijgc.bmj.com/content/32/Suppl_2/A430.1.full.pdf}, journal = {International Journal of Gynecologic Cancer} }