Early prediction of local control in head and neck cancer after chemoradiotherapy by FDG-PET.

OBJECTIVE

To determine the utility of 2-deoxy-2-[F]fluoro-D-glucose positron emission tomography (FDG-PET) for assessment of early locoregional clinical outcome of chemoradiotherapy for head and neck squamous cell carcinomas (HNSCCs).

METHODS

From July 2002 to July 2008, a total of 35 patients with HNSCCs underwent FDG-PET before and between 4 and 7 weeks (median: 5 weeks) after the end of concurrent chemoradiotherapy. FDG uptake of primary sites and metastatic lymph nodes was measured as standardized uptake values (SUVs) and was analyzed in relation to local control.

RESULTS

Visual inspection showed a sensitivity of 88.2% and a negative predictive value of 93.1%, but the positive predictive value was only 37.5%. Setting a posttreatment SUV of 3.0 and percentage change of 60 as cut-off values, positive predictive value increased to 81.3% and overall accuracy increased to 89.9% using the combined analysis of these two parameters. The local control rate was not associated with T, the N category, or the tumor node metastasis stage. In contrast, combined analysis of the posttreatment SUV and the percentage change in SUV was a useful indicator of locoregional control. In particular, combined evaluation of SUVs was very effective for assessment of therapeutic effects with reference to metastatic lymph nodes.

CONCLUSION

Early follow-up with FDG-PET is thus considered helpful further in choosing optimal therapy and for making an accurate prognosis.