Title: Comparison of Ultrasonography with CT, MRI and Pet in Cervical Lymph Node Staging of Head and Neck Cancer
Abstract: The correct preoperative N staging is crucial for the patients with head and neck cancer to determine if the neck dissection is necessary or not. This study aims to compare imaging modalities for staging the neck of patients evaluated by CT/MRI/PET and ultrasonography with the histopathologicl findings of the neck dissection specimens. Between April 2015 and March 2017, 150 newly diagnosed head and neck patients received regular pretreatment images with CT/MRI/PET and Ultrasonography in one tertiary medical center were enrolled. There are 80 patients received the surgical treatment. Neck dissections were performed on 60 patients. In these patients, 26 received computed tomography (CT) examination, 46 have magnetic resonance image (MRI) images and all of them accepted cervical ultrasonography preoperatively. Meanwhile, Positron Emission Tomography (PET) was also done on 23 patients in the preoperative status. There are 55 cases of oral cavity cancer, 9 cases of hypopharyngeal cancers, 4 cases of oropharyngeal cancers, 2 cases of laryngeal cancer, 5 cases of parotid cancer, 3 cases of submandibular gland cancer, 2 cases of sinunasal cancer and one case of sublingual cancer. And one patient got synchronous palate and hypopharyngeal cancer. Understaging of the N stage of nasopharyngeal carcinoma (NPC) by Ultrasonography was noted due to the limitation of evaluating of retropharyngeal space lymph nodes. Based on histopathologyical findings of neck specimens or the N0 neck was confirmed after more than 6 months clinical follow-up, ultrasonography, MRI, CT and PET correctly identified cervical lymph node metastases with a sensitivity of 85.19% (specificity 81.13%), 71.43% (specificity 81.25%), 80% (specificity 100%) and 75% (specificity 80%) respectively. The accuracy of ultrasonography, MRI, CT and PET were 82.5%, 92.3%, 78.26% and 78.26%. Ultrasonography has the highest sensitivity of preoperative N staging in the image modalities in this study. It also has comparable specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy with MRI and PET. Since the ultrasound is convenient, has high approachability and is a noninvasive technique in the clinical practice, it should be considered to add in the preoperative survey of head and neck cancers routinely. The ultrasonography has the significant dominance to help head and neck surgeons to realize the disease more comprehensively before the operation and may change the decision making of the surgical plan.