Utility of positron emission tomography for the detection of disease in residual neck nodes after (chemo)radiotherapy in head and neck cancer

Background. This study evaluates the utility of fluorine-18 fluorodeoxyglucose positron emission tomography (FDG PET) in patients with a node-positive mucosal head and neck squamous cell carcinoma who achieved a complete response at the primary site but had a residual mass in the neck 8 weeks or more after definitive (chemo)radiotherapy. Methods. Between October 1996 and July 2002, 39 eligible patients were identified. The reference PET scan was performed at a median of 12 weeks (range, 8-32 weeks) after treatment. Results. PET showed no metabolic activity in the residual mass in 32 patients. Five of these patients had a neck dissection and were all pathologically negative. The remaining 27 patients were observed for a median of 34 months (range, 16-86 months), with only one locoregional failure. The negative predictive value of PET for viable disease in a residual anatomic abnormality was 97%. Conclusion. Patients who have achieved a complete response at the primary site but have a residual abnormality in the neck that is PET negative approximately 12 weeks after treatment do not require neck dissection and can be safely observed. (C) 2004 Wiley Periodicals, Inc.