Association of Margin Status with Receipt of Adjuvant Radiation and Survival in Early-Stage Vulvar Cancer (103)

Abstract

<b>Objectives:</b> Surgery is the mainstay of treatment for early-stage vulvar cancer. Adjuvant radiation is thought to improve survival for patients with positive margins; however, recent studies have called this into question. We aimed to evaluate the association of adjuvant radiation and margin status with overall survival in a contemporary cohort. <b>Methods:</b> A retrospective cohort study was performed among women with vulvar cancer identified from the National Cancer Database between 2004 and 2017. Patients with stage I and II disease, with a tumor diameter ≤4cm, and squamous histology who underwent lymph node assessment were included. Bivariable tests were used to examine associations. Cox proportional hazard regression was used to evaluate the effect of adjuvant radiation on overall survival. <b>Results:</b> Of 9,567 patients with early-stage squamous vulvar cancer who underwent lymph node assessment, 7.4% had positive margins (<i>n</i> = 709). Among those with positive margins, 27.9% received adjuvant radiation. Receipt of adjuvant radiation was not associated with older age, non-White race, or lack of insurance; however, it was associated with stage II disease (32.8% vs 20.0%), higher grade (21.7% vs 15.1%), and lymph vascular space invasion (18.8% vs 11.7%, all p<0.04). Moreover, receipt of adjuvant radiation was not associated with improved overall survival in patients with positive margins (HR: 1.01, 95% CI: 0.73-1.40). This did not change after adjustment for stage, grade, and presence of lymph vascular space invasion (HR: 0.70, 95% CI: 0.43-1.16). <b>Conclusions:</b> Adjuvant radiation did not improve overall survival in patients with early-stage squamous vulvar cancer and positive margins.