OBJECTIVES: To assess the accuracy of the ultrasound examination in the prediction of lymph node status (LN) in vulvar cancer patients.
METHODS: This is a single institution retrospective observational study, conducted between December 2010 to January 2016. All women with a histological diagnosis of vulvar cancer triaged to inguinal surgery within 30 days from an ultrasound evaluation were included in the study. For each groin, 15 morphological and dimensional sonographic parameters of suspicion for lymph node involvement were examined. A Morphometric Ultrasound Pattern was expressed classifying the inguinal LN status in five groups, according to subjective judgment and then stratified in a positive/negative binomial judgment (MBA). In cases of positive MBA, a cytology was performed. Combining the information obtained from Morphometric Ultrasound Pattern and cytological results, a binomial Final Overall Assessment (FOA) was assigned for each groin. The final histology was considered as the reference standard. Patients with negative LNs and those with positive LNs, at histology, were compared and receiver-operating characteristics (ROC) curves were generated for statistically significant variables on univariate analysis to evaluate their diagnostic ability to predict negative LN status.
RESULTS: 144 patients were included: 87 of them had negative inguinal LNs at histology and 57 had positive LNs. A total of 256 groins were analyzed: at histology 171 were negative and 85 showed at least one metastatic LN. The following parameters showed the best accuracy, with the best balance between specificity and sensitivity: cortex thickness of the dominant lymph node (cut-off = 2.5 mm) (sensitivity 90.0% and specificity 77.9%), the short axis (cut-off = 8.4 mm) (sensitivity 63.9% and specificity 90.6%), the Cortex/Medulla ratio (cut-off = 1.2 mm) (sensitivity 70.4% and specificity 91.5%), the combination of Short axis and Cortex/Medulla ratio (sensitivity 88.9% and specificity 82.4%), and the FOA analysis (sensitivity 85.9% and specificity of 84.2%).
CONCLUSION: Our results demonstrate that preoperative ultrasound with or without the combination of cytology have a high accuracy in assessing inguinal LNs in patients with vulvar cancer. In particular, the combination of two ultrasound parameters (Short axis and Cortex/Medulla ratio) provided the highest accuracy in discriminating negative and positive lymph nodes. This article is protected by copyright. All rights reserved.