Prognostic value of lymph node ratio and number of positive inguinal nodes in patients with vulvar cancer

Abstract

To estimate the prognostic significance of lymph node ratio and number of positive nodes in vulvar cancer patients. This international multicenter retrospective study included patients diagnosed with vulvar cancer treated with inguinal lymphadenectomy. Lymph node ratio (LNR) is the ratio of the number of positive lymph nodes (LN) to the number of removed LN. Patients were stratified into risk groups according to LNR. LNR was correlated with clinical-pathological parameters. Survival analyses were performed. This analysis included 745 patients. In total, 292 (39.2%) patients had positive inguinal LN. The mean (SD) number of resected and positive LN was 14.1 (7.6) and 3.0 (2.9), respectively. High LNR was associated with larger tumor size and higher tumor grade. Patients with LNRs 0% (N0), >0<20%, and >20% had 5-year overall survival (OS) rates of 90.9%, 70.7%, and 61.8%, respectively (P<0.001). LNR was associated with both local and distant recurrence-free survival (P<0.001). Patients with 0, 1, 2, 3 or >3 positive lymph nodes had 5-year OS rates of 90.9%, 70.8%, 67.8%, 70.8% and 63.4% respectively (P<0.001). In multivariate analysis, LNR (P=0.01) and FIGO stage (P<0.001), were associated with OS, whereas the number of positive nodes (P=0.8), age (P=0.2), and tumor grade (P=0.7), were not. In high-risk patients, adjuvant radiotherapy was associated with improved survival. LNR provides useful prognostic information in vulvar cancer patients with inguinal LN resection in vulvar cancer. LNR allows for more accurate prognostic stratification of patients than number of positive nodes. LNR seems useful to select appropriate candidates for adjuvant radiation.