561P When to treat the pelvis in node-positive vulvar cancer: Results from the AGO-VOP.2 QS vulva study

Abstract

The population at risk for pelvic disease in vulvar cancer is poorly described. This results in an overtreatment of a considerable proportion of patients with groin-positive disease. In this retrospective, multicenter analysis, 306 patients with primary node-positive vulvar squamous cell carcinoma (VSCC) after surgical groin staging treated at 33 gynecologic oncology centers in Germany between 2017- 2019 were analyzed with regard to pelvic treatment, risk for pelvic nodal involvement and prognosis. The majority had locally restricted tumors (T1b/T2; 292/306; 95.4%) with a median tumor diameter of 32 mm (2-110mm). Nodal status of the groin(s) was as follows: 23.9% (73/306) pN1a, 23.5% (72/306) pN1b, 20.4% (62/306) pN2a/b, and 31.9% (97/306) pN2c/pN3 (TNM staging system version 6). Only 35.6% (109/306) received a pelvic LAE – 39.4% unilaterally and 60.6% bilaterally; pelvic nodal involvement was observed in 18.5%. None of the patients with one intranodal metastasis or 2 metastases <5mm and pelvic LAE showed pelvic nodal involvement. Taking only patients with more inguinal disease into account, the rate of pelvic involvement was 25%. In total, adjuvant RT was applied in 64.4% (197/306). Only half of the patients who received pelvic LAE and had positive pelvic nodes received adjuvant RT to the pelvis (50%, 10/20 patients); 41.9% (122/291 patients) experienced recurrent disease or died. In patients with histologically confirmed pelvic metastases after LAE, distant recurrences were most frequently observed (7/20 recurrences). In case of histologically detected groin metastases, the risk for pelvic metastasis is low. These data no longer justify uncritical treatment of the pelvis - neither with surgery nor radiotherapy- in groin node-positive vulvar cancer.