Sonographic examination of the neck after definitive radiotherapy for node-positive oropharyngeal cancer.

BACKGROUND AND PURPOSE Radiographic determination of viable disease in cervical adenopathy following RT for head and neck cancer can be challenging. The purpose of this study was to evaluate the utility of US, with or without FNA, in regard to the postradiotherapy effects on documented metastatic adenopathy in patients with oropharyngeal cancer. MATERIALS AND METHODS This study included 133 patients with node-positive oropharyngeal cancer who were irradiated from 1998 to 2004. Sonographic evaluation was performed within 6 months of completion of radiation. Posttreatment US results were compared with pretreatment CT images and were recorded as the following: progression, suspicious, indeterminate, posttreatment change, or regression (positive) versus nonsuspicious or benign (negative). FNAC was classified as nondiagnostic, negative, indeterminate, or positive. Results of US and US-guided FNAC were correlated with findings at neck dissection and disease outcome. RESULTS Of 203 sonographic examinations, 90% were technically feasible and yielded a nonequivocal imaging diagnosis. Of 87 US-guided FNAs, 71% yielded a nonequivocal tissue diagnosis. The PPV and NPV of initial posttreatment US were 11% and 97%. Sensitivity and specificity were 92% and 28%. The PPV and NPV of US-guided FNA were 33% and 95%, and the sensitivity and specificity were 75% and 74%. On serial sonographic surveillance, of 33 patients with nonsuspicious findings, only 1 (3%) had neck recurrence. Of 22 patients with questionable findings on CT and negative findings on US, none had a neck recurrence. CONCLUSIONS In experienced hands, serial US is an inexpensive noninvasive reassuring follow-up strategy after definitive head and neck RT, even when CT findings are equivocal.