Early Prediction of Response to Chemoradiotherapy for Head and Neck Cancer Reliability of Restaging With Combined Positron Emission Tomography and Computed Tomography

Objective To assess the role of combined positron emission tomography and computed tomography (PET-CT) in predicting early treatment response at the primary site and in the neck after chemoradiotherapy (CRT) for advanced squamous cell carcinoma of the head and neck (SCCHN). Design Retrospective analysis with a median follow-up of 24 months. Setting Academic, tertiary referral center. Patients and Interventions Thirty-one patients who were treated with concomitant intra-arterial CRT underwent PET-CT 6 to 8 weeks after the completion of treatment. Patients with findings on the physical examination, CT, or PET-CT indicative of persistent disease underwent appropriate surgical intervention for pathological assessment. Patients with a complete clinical response were observed with routine follow-up physical examination for disease recurrence. No evidence of disease at least 6 months after the completion of PET-CT was considered confirmation of complete clinical response. Main Outcome Measures Presence or absence of residual or recurrent disease during the follow-up period was used to calculate the sensitivity, specificity, and positive and negative predictive values of PET-CT for the primary site and the neck. Results Assessment of tumor response at the primary site with PET-CT had a sensitivity, specificity, and positive and negative predictive values of 83%, 54%, 31%, and 92%, respectively. In patients with pretreatment N1 to N3 disease, the sensitivity, specificity, and positive and negative predictive values of posttreatment PET-CT were 75%, more than 94%, more than 75%, and 94%, respectively, and the specificity and negative predictive value for patients with pretreatment N0 disease in the neck were 92% and more than 92%, respectively. Conclusions Negative PET-CT findings accurately determine early disease response at the primary site and in the neck. False-positive findings are common at the primary site. Patients with a negative PET-CT finding after the completion of intra-arterial CRT do not require surgical intervention.