ORIGINAL ARTICLE PET-CT VS CONTRAST-ENHANCED CT: WHAT IS THE ROLE FOR EACH AFTER CHEMORADIATION FOR ADVANCED OROPHARYNGEAL CANCER? Amy Y. Chen, MD, MPH, 1 Isabel Vilaseca, MD, 2 Patricia A. Hudgins, MD, 3 David Schuster, MD, 3 Ragheev Halkar, MD 3 1 Department of Otolaryngology, Emory University School of Medicine, Emory Otolaryngology, 1365A Clifton Rd NE, Ste 2315A, Atlanta, GA 30322. E-mail: amy.chen@emory.edu 2 Department of Otorhinolaryngology, Hospital Clinic I Universitari, Barcelona, Spain 3 Department of Radiology, Emory University School of Medicine, Atlanta, Georgia Accepted 24 August 2005 Published online 17 April 2006 in Wiley InterScience (www.interscience.wiley.com). DOI: 10.1002/hed.20362 Abstract: Purpose. The aim of our study was to assess the utility of positron emission tomography (PET) and 2 fluoro-2- deoxy-D-glucose coupled with neck CT compared with contrast- enhanced CT in predicting persistent cancer either at the pri- mary site or cervical lymphatics in patients with oropharyngeal cancer treated with concurrent chemoradiation. Methods. Thirty consecutive patients underwent clinical ex- amination, PET-CT, and contrast-enhanced CT to assess response after the completion of the treatment. The outcome variable was positive tissue diagnosis or negative disease at 6 months. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy were calculated for the primary site as well as cervical disease. Results. Contrast-enhanced CT alone showed the best ac- curacy in detecting disease at the primary site after treatment (85.7%). Accuracy in evaluating residual tumor in the cervical lymphatics for contrast-enhanced CT and PET-CT was 59.3% and 74.1%, respectively. For evaluating the neck, PET-CT and contrast-enhanced CT demonstrated 100% NPV, but the PPV was 36.3% and 26.6%, respectively. Conclusions. In this preliminary study, PET-CT seems to be superior to contrast-enhanced CT in predicting persistent dis- ease in the neck after chemoradiation for oropharyngeal or unknown primary cancer, but not at the primary site. However, the possibility of a false-positive result in the neck remains high, and thus overtreatment may result. Even more concerning are the false-negative results. Larger, prospective studies will be im- portant in defining the role of PET-CT in obviating the need for salvage neck dissections after chemoradiation. V V C 2006 Wiley Periodicals, Inc. Head Neck 28: 487–495, 2006 Keywords: computed tomography; PET-CT; oropharyngeal car- cinoma; chemoradiation Organ preservation protocols have become the standard therapy for many patients with advanced oropharyngeal cancer. However, the need for sal- vage surgery after treatment still remains contro- versial. Residual lymph nodes detected by physical examination, MRI, or CT may have persistent dis- ease or successfully treated tumor, 1,2 but there is not currently a definitive way to differentiate the two without biopsy. A similar situation may occur at the primary site, where the presence of edema, mucositis, or ulceration makes the diagnosis of Correspondence to: A. Y. Chen Presented at the 6th International Conference on Head and Neck Can- cer, August 9, 2004, Washington, DC. V V C 2006 Wiley Periodicals, Inc. PET-CT vs Contrast-Enhanced CT HEAD & NECK—DOI 10.1002/hed June 2006 487