Objective
To assess the accuracy of preoperative ultrasound examination for predicting lymph‐node (LN) status in patients with vulvar cancer.
Methods
This was a single‐institution retrospective observational study of all women with a histological diagnosis of vulvar cancer triaged to inguinal surgery within 30 days following ultrasound evaluation between December 2010 and January 2016. For each groin examined, 15 morphological and dimensional sonographic parameters associated with suspicion for LN involvement were examined. A morphometric ultrasound pattern (MUP) was expressed for each groin, classifying the inguinal LN status into five groups (normal; reactive‐but‐negative; minimally suspicious/probably negative; moderately suspicious; and highly suspicious/positive) according to subjective judgment, followed by stratification as positive or negative for metastasis according to morphometric binomial assessment (MBA). In cases of positive MBA, fine‐needle aspiration cytology was performed. Combining the information obtained from MUP and cytologic results, a binomial final overall assessment (FOA) was assigned for each groin. The final histology was considered as the reference standard. Comparison was performed between patients with negative and those with positive LNs on histology, and receiver‐operating‐characteristics curves were generated for statistically significant variables on univariate analysis, to evaluate their diagnostic ability to predict negative LN status.
Results
Of 144 patients included in the analysis, 87 had negative inguinal LNs and 57 had positive LNs on histology. A total of 256 groins were analyzed, of which 171 were negative and 85 showed at least one metastatic LN on histology. The following parameters showed the greatest accuracy, with the best balance between specificity and sensitivity, in predicting negative LN status: cortical (C) thickness of the dominant LN (cut‐off, 2.5 mm; sensitivity, 90.0%; specificity, 77.9%); short‐axis (S) length of the dominant LN (cut‐off, 8.4 mm; sensitivity, 63.9%; specificity, 90.6%); C/medulla (M) thickness ratio of the dominant LN (cut‐off, 1.2 mm; sensitivity, 70.4%; specificity, 91.5%), the combination of S length and C/M thickness ratio (sensitivity, 88.9%; specificity, 82.4%); and the FOA analysis (sensitivity, 85.9%; specificity, 84.2%).
Conclusions
Preoperative ultrasound assessment, with or without the addition of cytology, has a high accuracy in assessing inguinal LN status in patients with vulvar cancer. In particular, the combination of two ultrasound parameters (S length and C/M thickness ratio) provided the greatest accuracy in discriminating between negative and positive LNs. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.
