FDG PET/CT in patients with head and neck squamous cell carcinoma after primary surgical resection with or without chemoradiation therapy

OBJECTIVE. The purpose of this study was to assess the value of posttreatment FDG PET/CT in patients with squamous cell carcinoma of the head and neck (HNSCC) treated with primary surgical resection with or without adjuvant concurrent chemoradiotherapy. MATERIALS AND METHODS. A total of 98 HNSCC patients were treated with primary surgical resection and had undergone PET/CT within 6 months of treatment completion. The accuracy of the scans and the added value to clinical assessment and impact on management were established based on the clinical information before and after each scan. Overall survival of patients was estimated with Kaplan-Meier curves. RESULTS. Of the total 98 scans, 25 (25.5%) were interpreted as positive and 73 (74.5%) as negative. The sensitivity of posttreatment PET/CT was 80.0%; specificity, 89.5%; positive predictive value, 66.7%; negative predictive value, 94.4%; and accuracy, 87.5%. These scans were helpful in excluding tumor in 31.8% of patients with clinical suspicion of residual disease and identifying suspected residual disease in 13.2% of patients with no prior clinical suspicion. Multivariate regression analysis showed that tumor size, grade (p = 0.041), scan type (p = 0.002), and scan result (p = 0.005) were independent covariates associated with overall survival. Kaplan-Meier analysis showed a significant difference and association in overall survival between patients with a positive versus a negative posttherapy PET/CT scan result (hazard ratio, 5.65; 95% CI, 2.48-12.83; log rank Mantel-Cox p < 0.001). CONCLUSION. Posttreatment FDG PET/CT results had a high negative predictive value, added value to clinical assessment of 35% of patients, influenced subsequent management, and were associated with survival outcome of HNSCC patients treated with primary surgical resection.