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. © 2004 Wiley Periodicals, Inc. Head Neck 27: 175–181, 2005