The benefit of adjuvant radiation therapy in single-node-positive squamous cell vulvar carcinoma

Objective.To determine if adjuvant radiotherapy improves the survival of women with invasive squamous cell carcinoma of the vulva involving one inguinal node.Methods.Demographic, pathologic, and treatment information was obtained on patients with vulvar cancers from the Surveillance, Epidemiology, and End Results database between 1988 and 2001. Kaplan–Meier estimates and Cox-proportional hazards model were used for analyses.Results.Of the 490 patients with stage III, node-positive vulvar cancers, 208 had a single positive inguinal node. The median age of this group was 71 years (range: 29–100). 82.2% of patients were White, 7.2% were Hispanic, 7.7% were Black, 1.4% were Asian, and 1.4% were Others. 91.8% of patients underwent a radical vulvectomy with a unilateral or bilateral inguinal lymphadenectomy. The median number of lymph nodes resected was 13 (range: 1–34). 102 women underwent adjuvant radiotherapy, while 106 did not receive any radiation treatment. Women who received adjuvant radiotherapy had a 5-year disease-specific survival of 77.0% compared to 61.2% in those without radiotherapy (p = 0.02). After stratifying the study group based on the extent of lymphadenectomy, we found that radiation treatment improved the survival of those with ≤ 12 lymph nodes removed (76.6% versus 55.1%, p = 0.035). In those with more than 12 nodes resected, radiotherapy increased the survival from 66.7% to 77.3%, though this difference was not statistically significant (p = 0.23). In multivariate analysis, younger age (p = 0.01) remained as a significant prognostic factor for improved survival; however, adjuvant radiotherapy had a borderline significance (p = 0.06).Conclusion.Our data suggest that adjuvant radiotherapy may improve the disease-specific survival of patients with single-node-positive vulvar cancer who underwent a less extensive lymph node resection (≤ 12 nodes removed).