The contribution of second generation echo enhancers to the assessment of the true nodal status in HNSCC-patients

Introduction: For proper treatment of head and neck squamous cell carcinomas (HNSCC) the dissection of cervical lymph nodes in patients with clinically negative neck is mandatory even if in many cases histopathologic investigation of the dissected lymph nodes remains negative. Approximation of the performance of preoperative imaging modalities to the golden standard of microscopic evaluation has the promise for saving noninvolved necks from unnecessary surgical interventions in the future. We therefore sought to determine the contribution of contrast enhanced ultrasound in the nodal staging of HNSCC patients.

Patients and methods: 36 lymph nodes of 33 HNSCC patients were included in the study. After thorough sonographic examination of the neck including B-mode, Power-Doppler and Color Duplex Sonography one (in 3 patients: 2) lymph node was selected that was not surely classifiable by these modalities as tumor-free or metastatically afflicted. The lymph node was analysed using the phase inversion technique at low MI upon a bolus injection of 4,8ml SonoVue (Bracco) by a 3–8MHz probe with the Technos MPX-system and contrast kinetics were analysed by the ImageLab-software (both Esaote Biomedica, Germany).

Results: Several contrast parameters were significantly associated with metastatic disease as the AUC (p=0,03) or the slope of the wash-in-curve (p=0,0007). In several of the positive lymph nodes tumor growth was clearly demonstrated by perfusion defects.

Conclusion: The additional information gained by the application of contrast agents provides objective and subjective evidence of metastatic tumor growth in cervical lymph nodes, yet the benefit for daily routine awaits further evaluation.