Background: The purpose of this study is to describe the preliminary findings of 99mTc-labeled ethylene dicysteine deoxyglucose (99mTc-EC-DG) performed four weeks after chemoradiotherapy in patients with locally advanced head and neck squamous cell carcinoma.
Methods: Review of nine patients with locally advanced head and neck squamous cell carcinomas imaged with 99mTc-EC-DG single photon emission computed tomography-computed tomography (SPECT-CT) at baseline before treatment and at four weeks after treatment completion was performed.
Results: At four weeks post-treatment, five patients had either decreased activity or no significant activity on 99mTc-EC-DG SPECT-CT and were considered to have responded to treatment, whereas four patients did not have significantly decreased uptake on 99mTc-EC-DG SPECT-CT and were considered to have not adequately responded to treatment. Among the five patients considered to have treatment response at four weeks, all were free of disease (true-negative). Among the four patients considered to have stable activity on 99mTc-EC-DG SPECT-CT at four weeks, two were designated as having no response or incomplete response (true-positive), and two were designated as having complete response (false-positive) on subsequent composite assessment.
Conclusions: The pilot data is promising but warrants further investigation of 99mTc-EC-DG SPECT-CT for the assessment of locoregional treatment response at four weeks in patients with locally advanced head and neck squamous cell carcinomas.
Keywords: 99mtc-ec-dg spect-ct; chemoradiation; head and neck; recurrence; squamous cell carcinoma.