Evaluation of 18F-FDG PET/CT and CT/MRI with Histopathologic Correlation in Patients Undergoing Salvage Surgery for Head and Neck Squamous Cell Carcinoma

(18)F-fludeoxyglucose (FDG) positron emission tomography (PET) is a sensitive and specific method for detecting active residual disease after chemoradiotherapy or radiotherapy, but few studies have accurately evaluated its diagnostic accuracy with histopathologic correlation. We therefore investigated the clinical utility of (18)F-FDG PET/computed tomography (CT) in patients undergoing salvage surgery for residual head and neck squamous cell carcinoma (HNSCC) after primary nonsurgical treatments. Thirty-nine patients who initially received chemotherapy (n = 23), radiotherapy (n = 3), or chemoradiotherapy (n = 13) were evaluated 8-28 weeks later by (18)F-FDG PET/CT and CT/magnetic resonance imaging (MRI) prior to salvage surgery to clear residual disease. These results were compared with those of histopathologic analysis of the primary tumor and neck dissection tissue samples. Of these 39 patients, 22 (56%) had residual primary tumor. The sensitivity, specificity and accuracy of (18)F-FDG PET/CT for detecting primary tumors were 91, 65, and 79%, respectively. Of 56 dissected heminecks, 37 (66%) had residual metastatic lymph nodes. (18)F-FDG PET/CT and CT/MRI had accuracies for positive heminecks of 91 and 75%, respectively (P = 0.004). On a cervical level-by-level-based analysis, (18)F-FDG PET/CT and CT/MRI had accuracies of 89 and 78%, respectively (P < 0.001); (18)F-FDG PET/CT had a specificity of 93% and a negative-predictive value of 92% for detection of positive levels. (18)F-FDG PET/CT is superior to CT/MRI in detecting residual nodal disease in head and neck squamous cell carcinoma patients undergoing salvage surgery. Accurate preoperative diagnosis using (18)F-FDG PET/CT may help to determine the extent of salvage surgery.