The Feasibility of 18F-FDG PET scans 1 month after completing radiotherapy of squamous cell carcinoma of the head and neck.

UNLABELLED Our purpose was to prospectively evaluate the efficacy of PET with (18)F-FDG 1 mo after the completion of radiotherapy in patients with squamous cell carcinoma of the head and neck (SCCHN). METHODS Ninety-seven patients underwent (18)F-FDG PET scans before and after radiotherapy for nondisseminated SCCHN. The first scans were obtained no more than 4 wk before the start of radiotherapy, and follow-up scans were obtained 1 mo after the completion of radiotherapy. (18)F-FDG PET images were analyzed using standardized uptake values (SUVs). All patients were followed for at least 6 mo or until death. RESULTS The median SUVs of preradiotherapy primary sites and nodes were 6.5 (range, 2.3-23.0) and 5.6 (range, 1.2-16.8), respectively. The median SUVs of postradiotherapy primary sites and nodes were 1.8 (range, basal status value to 9.7) and 1.8 (range, basal status value to 8.6), respectively. Evaluation of the postradiotherapy status of tumors in these SCCHN patients showed the sensitivity of (18)F-FDG PET to be 88%, the specificity to be 95%, and the overall diagnostic accuracy to be 94.9%. CONCLUSION Our results indicate that (18)F-FDG PET might be a valuable imaging method for evaluating the response to radiotherapy in patients with SCCHN. One month after the completion of radiotherapy is not too early for follow-up (18)F-FDG PET to be performed to evaluate the response to radiotherapy.