Trends in sentinel lymph node evaluation for vulvar melanoma in the United States from 2012 to 2018

To describe trends in type of lymph node assessment for vulvar melanoma over time and factors associated with sentinel lymph node biopsy (SLNB).

This is a retrospective cohort study of patients in the National Cancer Database (NCDB) with vulvar melanoma from 2012 to 2018. Type of lymph node evaluation, demographic and clinical characteristics, and characteristics of the treating institution were abstracted. Chi square and multivariate logistic regression were used to evaluate predictors of SLNB compared to inguinofemoral lymph node dissection (IFLD) and no lymph node evaluation.

A total of 1828 patients with vulvar melanoma were identified. Of those, 925 (50.6 %) underwent lymph node evaluation, 357 (38.6 %) with SLNB alone, 97 (10.5 %) with SLNB and IFLD, and 471 (50.9 %) with IFLD alone. Year of diagnosis, age, T stage, insurance status, facility type, and facility volume were significant predictors of use of SLNB in univariate analyses. Age, year of diagnosis, T stage and facility type remained significant in multivariate analysis. SLNB was most often performed for T1 and T2 lesions (31.3 % and 36.2 %, respectively), while only 19.6 % of T3, 1.3 % of T4, and 25.8 % of those with unknown T stage underwent SLNB. Survival outcomes were similar regardless of mode of lymph node assessment, but worse in those who received no assessment.

Current practice in the United States for lymph node evaluation in vulvar melanoma differs from the recommended guidelines for cutaneous melanomas by T stage. Updated guidelines for vulvar melanoma aligned with those for cutaneous melanoma are needed.