Declining Use of Inguinofemoral Lymphadenectomy in the Treatment of Clinically Negative, Pathologic Node Positive Vulvar Cancer: A National Cancer Database Analysis

Abstract

Inguinofemoral lymphadenectomy (IFL) is a morbid procedure, and studies support the use of sentinel lymph node biopsy (SLNB) as an initial staging procedure for women with early stage operable vulvar cancer. However, in the recently presented GROINSS-V II study, for patients with SLNB metastasis > 2 mm, groin radiotherapy with a total dose of 50 Gy was not a safe alternative to IFL due to an increased number of groin recurrences. Therefore, the management of patients with SLNB-positive groin disease remains controversial. We used the National Cancer Database (NCDB) to examine national trends in the use of SLNB, IFL, and adjuvant therapies in clinically node negative, pathologic node positive (cN-/pN+) vulvar cancer.The NCDB was used to identify patients with cN-/pN+ vulvar cancer between 2012 and 2017. Patients with benign histologies, Paget's disease, and melanoma were excluded. Demographic and clinical data were compared with the chi-squared and Wilcoxon rank-sum test. Overall survival (OS) was analyzed with the Kaplan-Meier method and log-rank test. Cox proportional hazards regression modeling was used to determine factors associated with OS.A total of 1,715 patients with cN-/pN+ vulvar cancer were identified. Of this group, sentinel lymph node data was recorded for 1,172 patients. The rate of SLNB with or without IFL increased from 10.2% in 2012 to 24.0% in 2017. The rate of patients who had SLNB alone increased from 3.4% to 15.1% and conversely, the rate of IFL +/- SLNB decreased from 96.6% to 84.9% (P < 0.05). The SLNB-alone cohort (n = 126) did not differ from the IFL +/- SLNB (n = 1046) cohort in terms of race, age, tumor size, margin status, treatment at academic vs. community center, income, insurance, and residence in a metropolitan or non-metropolitan area. Rates of adjuvant treatments were similar with radiation therapy utilized in 63.5% and 64.9% of the SLNB-alone and IFL +/- SLNB cohorts, respectively. Rates of adjuvant chemoradiation were 29.4% and 31.1% of the SLNB-alone and IFL +/- SLNB cohorts, respectively. Median follow-up was 29 months. On multivariate analysis, there was no significant difference in OS between patients who received SLNB-alone vs. those who received IFL +/- SLNB (HR:0.92, 95% CI: 0.7-1.3, P = 0.617).In this large national sample of vulvar cancer patients with cN-/pN+ groin disease, the rate of IFL is decreasing with time as SLNB is becoming more common and a majority receive either adjuvant radiation or chemoradiation. There was no significant difference in OS observed between patients who received SLNB-alone vs. those who received IFL +/- SLNB. Whether the favorable outcomes in the SLNB-alone cohort may be attributed to radiation technique and/or use of chemoradiation warrants further study.M. Mokhtech: None. S. Gao: None. M. Kassick: None. G. Menderes: None. S. Damast: None.